DE102014001581A1 - Method of execution with an internal combustion engine arranged for a cylinder deactivation operation - Google Patents

Abstract

A method of execution with an internal combustion engine arranged for a cylinder deactivation operation, wherein the internal combustion engine has a plurality of cylinders and is adapted to fire the cylinders in dependence on a respective current cylinder deactivation characteristic, wherein - in a first operating state with a first cylinder deactivation characteristic firing cylinders are fired in accordance with a predetermined injection target amount according to the first cylinder cutoff characteristic; At a state transition from the first operating state to a second operating state having a second cylinder deactivation characteristic, in which the cylinders are fired in accordance with a predetermined injection target quantity according to the second cylinder deactivation characteristic, at least the first cylinder which is to be fired after the state transition, is fired corresponding to a determined according to a characteristic of the state transition individual injection target set for smoothing the state transition due to disturbed speed curve; and subsequently, in the second operation state, the cylinders to be fired are fired in correspondence with the predetermined target injection amount according to the second cylinder cut-off characteristic.

Description

The present invention relates to a method of execution with an internal combustion engine arranged for a cylinder deactivation operation according to the preamble of claim 1.

In generic internal combustion engines, in particular rapid-fire units, it may whenever the Zylinderabschalt characteristic changes, d. H. in the transition from one cylinder bank to the other cylinder bank (in the case of an alternate cylinder deactivation) or in the transition from full engine operation to Zylinderabschalt operation or vice versa in the transition from Zylinderabschalt operation to full engine operation come to undesirable engine speed disturbances. The engine speed may rise or fall for a short time.

Particularly in the case of rapid standby units, which are driven by means of an overrunning clutch, the overrunning clutch may continue to open during an alternating cylinder deactivation when changing over from one cylinder bank to the other. This unwanted process is with 1 in synopsis with 2 In more detail: a 16-cylinder engine is operated in cylinder deactivation operation stationary at the speed 1500 l / min. First, only the cylinders of the front half of the engine are fired, ie the cylinders A1 to A4 and B1 to B4 (front cylinder bank). This is indicated by two binary coded variables "Active Cylinder Bank A" and "Active Cylinder Bank B", which both assume the value (digit) 15 (1 + 2 + 4 + 8) and are represented by the lower curve. If both variables change from the value 15 to the value 240 (16 + 32 + 64 + 128), then only the cylinders of the rear half of the engine are fired, while the cylinders of the front half of the engine are no longer fired. In this case, it is thus switched from the front half of the engine to the rear half of the engine and from the front cylinder bank to the rear cylinder bank. 1 shows that the engine speed, ie the speed of the internal combustion engine, briefly increases in this switching operation and then drops sharply.

In this case, the drop in the engine speed is a consequence of the short-term speed increase. The reason for this is that high-speed standby units require a very "fast" speed controller due to high load switching demands. This has the consequence that the injection quantity is already greatly reduced even with small speed increases. This reduction of the injection quantity leads to the in 1 shown speed drop and finally to the opening of the one-way clutch.

Based on this, the present invention has the object to avoid a significant disturbance in the course of the engine speed in connection with a state transition from a Zylinderabschaltzustand to another Zylinderabschaltzustand.

This object is achieved by the method having the features of claim 1.

Advantageous developments and embodiments of the invention are specified in the further claims.

According to the invention, a method is proposed for execution with an internal combustion engine set up for a cylinder deactivation operation, wherein the internal combustion engine has a plurality of cylinders and is set up to fire the cylinders as a function of a respective current cylinder deactivation characteristic, d. H. preferably via injection of fuel into the cylinders or combustion chambers of the internal combustion engine. Possible with the internal combustion engine representable Zylinderabschalt characteristics are z. B. - as mentioned above - the operation with only one or only the other cylinder bank and the full engine operation.

The internal combustion engine is preferably provided with a rapid-response unit or forms such, in particular a rapid-response unit with an overrunning clutch.

The method is characterized in that, in a first operating state with a first cylinder deactivation characteristic, the cylinders to be fired are fired in correspondence with a predetermined setpoint injection quantity according to the first cylinder deactivation characteristic; at a state transition from the first operating state to a second operating state having a second cylinder deactivation characteristic, in which the cylinders are fired in accordance with a predetermined target injection quantity according to the second cylinder deactivation characteristic, at least the first cylinder to be fired after the state transition is corresponding is fired with an individual (or modified) setpoint injection quantity determined as a function of a characteristic of the state transition for a smoothing of the state transition-related disturbed speed profile; and subsequently, in the second operation state, the cylinders to be fired are fired in correspondence with the predetermined target injection amount according to the second cylinder cut-off characteristic.

The method is in particular for carrying out during a stationary operation of Internal combustion engine provided, ie preferred in (permanent or continuous) operation. Within the scope of the method, the respective nominal injection quantity of a respective (first / second) operating state - with the exception of firing with the individual desired injection quantity - thus remains essentially unchanged or constant, ie, uniformly, for the duration thereof (stationary operation).

A state transition in the context of the invention continues - as mentioned above - z. As in the transition from one operation with a cylinder bank to operate with another cylinder bank (in the case of an alternate cylinder deactivation) or the transition from a full engine operation to a Zylinderabschalt operation (activation cylinder deactivation) or vice versa at a transition from Zylinderabschalt operation to a full engine operation (deactivation cylinder deactivation) before. Also included is a transition from full engine operation and back during the alternate cylinder deactivation.

Furthermore, in the context of the invention, a respective (individual) injection target quantity is also used to define a respective (individual) injection quantity, ie. H. the (individual) injection target quantity represents an (individual) injection quantity.

By the invention, the engine speed is effectively smoothed in the case of a state transition in the context of a Zylinderab- or -connection. As a result, it is furthermore advantageously avoided that an overrunning clutch unintentionally opens when there is an alternating cylinder deactivation when a state transition takes place. Furthermore, it is advantageously possible to provide a speed signal with an improved pendulum width and extent in the DIN ISO 8528-5 Adhere to specified limits for the quality of the speed signal (speed swing width).

According to a further advantageous aspect of the method according to the invention, the individual desired injection quantity is determined on the basis of the injection set quantity (of the first operating state) valid before the state transition. In the context of the method, provision is made in particular for the new or individual (temporarily applied) injection setpoint to be a reduced injection setpoint compared to the predetermined setpoint injection setpoint of the first (previous) operating state in the case of a state transition characteristic which can be expected to increase speed due to the state transition.

Furthermore, it is also provided that, in the case of a state transition characteristic which causes a speed drop due to the state transition, the individual target injection quantity is a larger injection target quantity than the predetermined target injection quantity of the first (previous) operating state.

With advantage, the firing with the new injection target quantity can take place at least for the duration of the (expected, state transition-related) disturbance and / or for the first two cylinders which are to be fired after the state transition.

According to a further advantageous aspect of the method according to the invention, the new injection target quantity is determined on the basis of the injection target set valid before the state transition, the injection target quantity valid before the state transition being weighted with a weighting factor to determine the new target injection quantity. In this case, preferred embodiments provide that the weighting factor is selected to be less than 1 in the case of a state transition characteristic which can be expected to increase the speed due to the state transition; and / or the weighting factor is selected to be greater than 1 in the case of a state transition characteristic which, due to the state transition, causes a drop in speed to be expected. By such a weighting, a state transition-dependent optimized, smoothed speed curve can be achieved with advantageously low computation effort. The weighting factor can be selected as a constant or as a function of the load.

The invention also proposes an internal combustion engine having a plurality of cylinders, wherein the internal combustion engine is set up for a cylinder deactivation operation, and wherein the internal combustion engine is set up to carry out the method as explained above. Preferably, the internal combustion engine is further configured to perform the method (in the context of state transitions) during stationary operation of the internal combustion engine.

Also proposed is a computer program product with program code for carrying out the method. The program code may preferably be implemented on an engine control unit (the internal combustion engine), eg. B. as a hardware and / or software solution.

Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, with reference to the figures of the drawings, which show details essential to the invention, and from the claims. The individual features can be realized individually for themselves or for several in any combination in a variant of the invention.

Preferred embodiments of the invention are explained below with reference to the accompanying drawings. Show it:

1 an example and schematically a diagram which illustrates a disturbance in the sense of a speed drop on the internal combustion engine according to the prior art in more detail.

2 exemplary and schematically with reference to two diagrams a) and b) a cylinder arrangement of an internal combustion engine.

3 exemplary and schematically a speed control loop, which is usable with a possible embodiment of the invention.

4 Exemplary and schematic diagram, illustrating the functionality of the engine management in more detail.

5 exemplary and schematically a waveform in alternating cylinder deactivation.

6 Exemplary and schematic diagrams a), b), c), based on which a disturbance in the speed curve is explained in more detail as a result of a first possible state transition.

7 Exemplary and schematic diagrams a), b), c), based on which a disturbance in the speed curve as a result of a second possible state transition is explained in detail.

8th Exemplary and schematic diagrams a), b), c), based on which a disturbance in the speed curve is explained in more detail as a result of a third possible state transition.

9 exemplary and schematic diagrams a), b), c), based on which a disturbance in the speed curve is explained in more detail as a result of a fourth possible state transition.

10 Exemplary and schematic diagrams a), b), c), based on which a disturbance in the speed curve is explained in more detail as a result of a fifth possible state transition.

11 Exemplary and schematic diagrams a), b), c), based on which a disturbance in the speed curve is explained in more detail as a result of a sixth possible state transition.

12 by way of example and schematically a diagram illustrating in more detail the functionality according to the invention for determining the new injection quantity.

13 Exemplary and schematic diagrams a), b), c), d), based on which the inventive smoothing of the disturbance in the speed curve example of the first possible state transition according to 6 is explained in more detail.

14 Exemplary and schematic diagrams a), b), c), d), based on which the inventive smoothing of the disturbance in the speed curve by way of example at the second possible state transition according to 7 is explained in more detail.

In the following description and the drawings, the same reference numerals correspond to elements of the same or comparable function.

2 Illustrates in the lower diagram a) by way of example, cylinders A1 to A8 of an A side and cylinders B1 to B8 of a B side of an internal combustion engine 1 (with so far 16 cylinders). A front engine half located on the clutch side (KS) 3 the internal combustion engine 1 consists of the cylinders A1 to A4 and B1 to B4. A rear engine half located on the clutch side (KGS) 5 includes the cylinders A5 to A8 and B5 to B8.

A relationship with the variables "Active Cylinder Bank A" and "Active Cylinder Bank B" according to the above-explained 1 is in the upper diagram b) of 2 produced. Each cylinder is assigned a binary weight according to this diagram b). Will the front half of the engine 3 fired, the value (digit) 15 (= 1 + 2 + 4 + 8) results for both variables, the rear half of the motor becomes 5 fired, both variables assume the value 240 (= 16 + 32 + 64 + 128). Thus, by the values of the variables "Active Cylinder Bank A" and "Active Cylinder Bank B" by the internal combustion engine 1 defined operating states, ie with an associated Zylinderabschalt characteristic.

3 now shows a usable with the invention speed control circuit 7 for the speed control of the internal combustion engine 1 , preferably implements with an engine control unit (not shown).

As part of the scheme of the internal combustion engine 1 is a target speed n _target of an actual speed n _is subtracted, resulting in a speed control deviation e results. This speed error e is the input of a PI (DT ₁ ) controller 9 , The PI (DT ₁ ) controller 9 has as further input variables, inter alia, a proportional coefficient kp and as an output variable a speed controller torque M _desired ^{PI (DT1)} . This is added with a load signal torque M _set ^load , where M _set ^{load represents} a disturbance variable. This feedforward control enables a system signal to improve the dynamics of the speed controller 9 be used.

The sum of M _set ^{PI (DT1)} and M _set ^load is then limited down to M _setpoint ^Min and up to M _setpoint ^Max , ie by a corresponding limiter 11 , To the limited setpoint torque M _Soll, finally, a frictional torque M _Soll is added ^friction, from which a corrected desired torque M _corr results. This is among other variables such as the engine speed n _{is the} input value of a functional unit "engine management", Bz. 13 , Output of the engine management 13 is an injection _target amount Q _target . One of these corresponding injection quantity is in the cylinders A1 ... B8 of the internal combustion engine 1 injected. The raw values n _{raw of} the engine speed are recorded and with the aid of a speed filter 15 in the Motoristdrehzahl n _is converted.

4 illustrates the engine management 13 closer.

Shown are two efficiency maps, the map "full engine" in full engine operation and the map "ZA" in Zylinderabschalt operation comes to the application. Both maps "full engine" and "ZA" have the engine speed n _is and the corrected target torque M _corr as input. The output variable of both maps is the injection nominal mass m _KF . The changeover between both maps is controlled by a signal "ZA active". Is the engine 1 in full motor mode, this signal has the logical value "False" and the switch S is in the upper position. Is the engine 1 in cylinder deactivation mode, this signal assumes the logical value "True" and the switch S is in the lower position.

The output value m _{KF of} the respective valid map is then multiplicatively corrected several times. Among other things, a correction in dependence on an air mass ratio, wherein in the functional unit "efficiency correction" a multiplicative correction factor f _{η is} calculated (the correction of the injection target mass as a function of the air mass ratio is in the non-prepublished document DE 10 2012 025 019.3 the contents of which are incorporated herein by reference in detail). Another, in 4 shown correction of the injection target mass m _KF takes place in dependence of the intake air T ₀ . In this case, a multiplicative correction factor f _{T is} calculated via a two-dimensional correction curve as a function of the intake air T ₀ .

If cylinders are switched off, the injection target mass is corrected as a function of the number of active cylinders. For this purpose, a multiplicative correction factor f _z is calculated from the total number of cylinders n _cyl ^total and the number of active cylinders n _cyl ^active : f _z = n _cyl ^total / n _cyl ^active

This means that for an operating condition with a cylinder deactivation characteristic in which half of the cylinders are not fired, a multiplicative correction of the injection target mass per cylinder is made by a factor of 2 compared to a full engine operating condition, i. H. In this case, the injection mass, which is twice the amount of full engine operation, is injected into the active cylinders.

The resulting injection _target mass m _Soll is finally converted into an injection _target quantity Q _{target as} a function of the fuel density and other variables.

Based on 5 to 11 the cause of the problem underlying the invention is explained below on the basis of exemplary operating states and state transitions on a conventional internal combustion engine, which cause could be successfully identified by the inventors.

5 First, by way of example, represents a signal which indicates which cylinder bank A or B is fired in the event of an alternating cylinder deactivation. If the cylinder bank A is fired (corresponding to a first operating state of the internal combustion engine 1 with a first cylinder deactivation characteristic), the signal has the value 0, the cylinder bank B is fired (corresponding to a second operating condition with a second cylinder deactivation characteristic), the signal has the value 1. At the expiration of the time Δt is from a cylinder bank A or B to the other bank B or A changed (state transitions).

6 shows a cylinder shut-off operation using the example of a 12-cylinder engine 1 in the case of alternating cylinder deactivation. The following ignition sequence is assumed:
A1 → B1 → A2 → B2 → A3 → B3 → A4 → B4 → A5 → B5 → A6 → B6

The corresponding firing angle sequence is assumed as follows: 30 ° → 90 ° → 30 ° → 90 ° → 30 ° → 90 ° → 30 ° → 90 ° → 30 ° → 90 ° → 30 ° → 90 °

The first diagram a) shows the ignitions of the individual cylinders as a function of the ignition angle φ. Here, the fired cylinders are hatched.

The second diagram b) shows the in 5 represented signal as a function of time t, which indicates whether the bank A or the bank B is fired.

The third diagram c) shows the engine speed n _is dependent on the time t.

Since the signal in diagram b) initially assumes the value 0, only the bank A is fired, ie the cylinders A1, A2 and A3 are fired at intervals of 120 °. At time t ₁ , the in 5 time described .DELTA.t expired, whereby in the sequence the cylinders of the cylinder bank B are fired, ie there is a state transition of an operating condition of the internal combustion engine 1 with a first cylinder deactivation characteristic (only bank A bank active) to a second operating condition with a second cylinder deactivation characteristic (only bank B bank active). This means that at the time t _2, the cylinder B3 is fired. At intervals of 120 °, the other cylinders of the cylinder bank B are then fired (B4, B5, ...).

The overall resulting firing order is as follows:
A1 → A2 → A3 → B3 → B4 → B5 → B6

The following ignition angles result for this:
120 ° → 120 ° → 30 ° → 120 ° → 120 ° → 120 °

The equidistant ignition interval of 120 ° is thus interrupted by a short or shorter ignition interval of 30 ° when switching from the cylinder bank A to the cylinder bank B. With the cylinders A3 and B3, two ignitions take place in rapid succession, as a result of which an increase in the engine speed n _{is produced} at the time t ₂ . This explains this on the basis of 1 described phenomenon.

The change or state transition from the cylinder bank A to the cylinder bank B takes place at equidistant intervals, for. B. every 10 minutes (see. 5 ) and thus time-synchronized. The control of the individual cylinders, however, takes place at certain ignition angles and thus angle synchronously. This asynchronism has the consequence that the change from the cylinder bank A to the cylinder bank B is not necessary before the firing angle of the cylinder B3, as in 6 shown must occur.

7 represents the case that the bank change after the firing angle of the cylinder B3, again at time t ₁ , takes place. In this case the following ignition sequence results:
A1 → A2 → A3 → B4 → B5 → B6

The following ignition angles now result:
120 ° → 120 ° → 150 ° → 120 ° → 120 °

The equidistant firing interval of 120 ° is thus interrupted by a longer firing interval of 150 ° when switching from the cylinder bank A to the cylinder bank B, ie a state transition takes place. With the cylinder B4 thus takes place a delayed ignition, which causes a drop in the engine speed n _is at time t ₂ .

Depending on when the state transition occurs, it can - s. 6 and 7 - So come with a change of the cylinder bank both to an increase and a decrease in engine speed.

8th shows, also for a 12-cylinder engine, the state transition from a first operating state with a first Zylinderabschalt characteristic, according to an operation of the internal combustion engine 1 with a number of deactivated cylinders (cylinder deactivation operation) to a second operating condition with a second cylinder deactivation characteristic, corresponding to a full engine operation. The diagram a) again shows the ignitions of the individual cylinders as a function of the ignition angle φ. Here, the fired cylinders are again hatched.

Diagram b) indicates whether cylinder deactivation operation or full engine operation is active. If the signal "ZA active" assumes the value 1, the cylinder deactivation mode is active, this signal assumes the value 0, then the full motor operation is active. At the time t ₁ , the signal "ZA active" changes from the value 1 to the value 0, ie at this point in time the state transition from the cylinder deactivation operation to the full engine operation takes place.

The diagram c) again shows the engine speed as a function of the time t.

The switchover from the cylinder deactivation operation to the full engine operation takes place at the time t ₁ , at which point the cylinder A3 has already ignited. Previously, the ignition of the cylinder A1 and A2 was carried out at a distance of 120 °. With the switching or the state transition to the full-engine operation at time t ₁ all cylinders are fired according to the firing order. The injection quantity per cylinder is approximately halved during the transition to full engine operation. The result is the following ignition sequence:
A1 → A2 → A3 → B3 → A4 → B4 → A5 → B5 → A6 → B6

These include the following ignition angles:
120 ° → 120 ° → 30 ° → 90 ° → 30 ° → 90 ° → 30 ° → 90 ° → 30 °

Considering the cylinder pairs A1, B1 and A2, B2, which are controlled during the cylinder shut-off operation and the cylinder pairs A4, B4 and A5, B5 and A6, B6, which are driven during full engine operation, it holds that in Zylinderabschalt Operation of the above-mentioned cylinder pairs in each case a cylinder is acted upon in about twice the injection quantity (A1, A2) and in full engine operation of the said pairs of cylinders in each case both cylinders are acted upon in about half the injection quantity.

Of the cylinders A3 and B3, between the firings of which the state transition from cylinder deactivation operation to full engine operation takes place, a cylinder (A3) is charged with approximately twice and a cylinder (B3) with approximately half the injection quantity. This means that this cylinder pair causes a higher energy input than the other cylinder pairs. This results after activation of the full engine operation with the beginning of the injection of the cylinder B3 at time t _2, an increasing engine speed, as shown in the diagram c).

9 shows the transition from Zylinderabschaltbetrieb to full engine operation, the transition in this case takes place after the firing angle of the cylinder B3. The result is the following ignition sequence:
A1 → A2 → A3 → A4 → B4 → A5 → B5 → A6 → B6

The ignition angles are as follows:
120 ° → 120 ° → 120 ° → 30 ° → 90 ° → 30 ° → 90 ° → 30 °

Now, during the cylinder shut-off operation, the cylinder pairs A1, B1 and A2, B2 and A3, B3 are controlled, of which in each case a cylinder approximately twice the injection quantity is injected (A1, A2, A3) and is not injected into a cylinder ( B1, B2, B3). During full engine operation, the cylinder pairs A4, B4 and A5, B5 and A6, B6 are driven, of which in each case in a cylinder about half the injection quantity is injected. Since in the transition from Zylinderabschalt-operation on the full engine operation on the cylinder A3, in which injected in about twice the injection amount, the cylinder A4, in which approximately only half the injection amount is injected follows, results in this case after activation of the full engine operation with the start of the ignition of the cylinder A4 at time t ₂ a falling engine speed, as shown in diagram c).

10 FIG. 12 shows a state transition from full engine operation (first operation state) to cylinder deactivation operation (second operation state), wherein the cylinder deactivation is activated at time t ₁ , that is, after the ignition angle of cylinder A3 and before the ignition angle of cylinder B3. Diagram b) shows that the signal "ZA active" changes from the value 0 to the value 1 at this time.

In the cylinders of the cylinder pairs A1, B1 and A2, B2 is injected in full engine operation about each half the injection quantity, while only in each case one cylinder of the cylinder pairs A4, B4 and A5, B5 and A6, B6 in Zylinderabschalt operation about the twice injection quantity is injected (B4, B5 and B6, see diagram a)). Since in the cylinders of the cylinder pair A3, B3 injected in about half (A3) and about twice (B3) injection quantity, the engine experiences 1 through this pair of cylinders a higher energy input, whereby the engine speed at the time t ₂ increases (see diagram c)).

11 also shows the transition from full engine operation (first operation state) to cylinder deactivation operation (second operation state), in which case the transition to the cylinder deactivation operation takes place after the ignition angle of cylinder B3 and before the ignition angle of cylinder A4 at time t1 (FIG. see diagrams a) and b)). In the cylinders of the cylinder pairs A1, B1 and A2, B2 and A3, B3 in each case approximately half the injection quantity is injected in full engine operation. Into the cylinders A4, A5 and A6 of the cylinder pairs A4, B4 and A5, B5 and A6, B6, approximately twice the injection amount is injected while the cylinders B4, B5 and B6 are not fired. Since in the transition from full engine operation to the cylinder cut-off operation on two cylinders with approximately half injection quantity (A3, B3), a cylinder with approximately double injection quantity (A4), it comes at time t ₂ , when the cylinder A4 ignites to an increase in the engine speed (see diagram c)).

The basis of the 6 to 11 Illustrated examples show that whenever the cylinder deactivation characteristic changes, ie during the transition from one cylinder bank to the other cylinder bank (in the case of the alternate cylinder deactivation) or at the transition from full engine operation to cylinder deactivation operation or vice versa at the transition from cylinder deactivation Operation for full engine operation may result in engine speed disturbances. The engine speed can be taken into account as a function of the characteristic of the respective transition (in the context of which the Zylinderabschalt characteristic or operating condition before and the Zylinderabschalt characteristic or the operating state after the transition and in particular also the time of transition during the firing order should) rise or fall for a short time. The respective state transition-specific characteristic is advantageously used for the invention insofar as a prediction of the type of disturbance to be expected (increase / decrease of the rotational speed) is now possible.

12 illustrates the basic idea of the invention in a diagram in more detail.

In a state transition from a first operating state with a first Zylinderabschalt characteristic in which the cylinder to be fired corresponding to a predetermined target injection amount according to the first cylinder cutoff characteristic, to a second operating condition having a second cylinder _cutoff characteristic in which the cylinders are fired in accordance with a predetermined _{target injection amount} according to the second cylinder _cutoff characteristic, a signal _cyl - for at least one subsequent to the state transition injection, ie temporarily, - the logical value "True" (T) and then again the logic value "trap" (F). If the signal signal _{zyl has} the value "True", then the switch S assumes the upper position and the resulting injection _{target quantity} Q _Soll ^Res , which is injected into the cylinders, is identical to the product of the _target injection quantity Q _Soll as output parameter of the engine management 13 (see. 3 and 4 ) and a weighting factor f _cyl : Q _set ^Res = f _cyl · Q _setpoint

This means that the engine management 13 calculated injection _setpoint Q Q is weighted for at least one injection after changing the Zylinderabschalt characteristic by the factor f _zyl . The weighting is carried out according to the invention ideally so that the injection _target amount Q _Soll in the case of an expected speed increase (ie, depending on a characteristic of the state transition as based on 6 . 8th . 10 and 11 described) reduced and in the case of an expected speed drop (ie, depending on a characteristic of the state transition as based on the 7 and 9 described) is increased.

Thus, with the invention, at least the first cylinder to be fired after the state transition corresponding to a new or individual (resulting from the weighting), depending on the characteristic of the state transition (expected speed increase or expected speed drop) is fired injection target set, d , H. for a smoothing of the state transition due disturbed speed curve.

As described above shows 6 the increase in the engine speed in the case of the alternating cylinder deactivation, ie when the state transition (change of the cylinder bank) takes place between two ignitions occurring in quick succession (cylinders A3 and B3).

13 In contrast, now illustrates how this speed increase can be reduced with the invention or a smoothing in the otherwise clearly troublesome speed curve can be brought about.

The diagram a) is identical to the diagram a) according to 6 , The diagram b) shows that the state transition from a first operating state with a first cylinder deactivation characteristic (only cylinder bank A active) to a second operating state with a second cylinder deactivation characteristic (only cylinder bank B active) at time t ₁ , ie after the ignition angle of the cylinder A3 and before the firing angle of the cylinder B3, takes place. In this case, the displayed signal changes from the value 0 to the value 1.

The diagram d) shows the individual injection cylinders to be metered resulting _target injection quantity Q _Soll ^Res . Until the time t ₁ , the cylinder bank A is active, ie the cylinders A1, A2 and A3 are acted upon or fired according to the predetermined injection _target quantity Q _setpoint = Q _ZA ^stat = Q _setpoint ^Res is about twice as large as the injection setpoint valid in full engine operation).

From the time t ₁ , the cylinder bank B is active, ie the next cylinder to be fired is the cylinder B3. In anticipation of a speed increase, that is, depending on the characteristic of the state transition, the currently valid injection _target ^amount Q _ZA ^{stat is} lowered at time t ₂ , for which purpose a new or individual (temporarily valid) injection target _quantity Q _Temp , s. above too 12 , determined and Q _Soll ^Res = Q _Temp = f _cyl * Q _ZA ^{stat is provided} for the firing of the cylinder B3. By weighting the previously applied injection _{target quantity} Q _target = Q _ZA ^stat with the factor f _zyl , the _target injection _quantity Q _ZA ^{stat is} thus lowered at time t ₂ , ie f _cyl is less than 1 in this case: 0 <f _cyl <1

At time t ₄ , the _target injection quantity Q _Soll ^{Res is raised} again to the original level Q _ZA ^stat , so that the next cylinder B4 to be fired is again charged with the original injection _target ^quantity Q _Soll ^Res = Q _ZA ^stat .

Diagram c) shows, dotted, the original course of the engine speed accordingly 6 as it results without the invention. The continuous course of the engine speed results in contrast, when the desired injection rate of the cylinder B3 is lowered according to the invention. It can be seen that the engine speed is advantageously and significantly smoothed by this measure.

As also described above 7 the drop in engine speed in the case of the alternate cylinder deactivation when the state transition (cylinder bank change) occurs between two large spaced firings (cylinders A3 and B4).

14 shows, in contrast, how this speed drop is reduced with the invention.

The diagram a) is identical to the diagram a) according to 7 , The diagram b) shows that the change from cylinder bank A to cylinder bank B takes place again at the time t ₁ , ie after the ignition of the cylinder A3 and before the ignition of the cylinder B4. In this case, the displayed signal changes from the value 0 to the value 1.

The diagram d) shows - as before at 13 - In turn, the individual injection cylinders to be metered resulting injection _target amount Q _Soll ^Res . Until the time t ₁ , the cylinder bank A is active, ie the cylinders A1, A2 and A3 are supplied with the _desired injection quantity Q _Soll ^Res = Q _ZA ^Stat (this injection _target ^quantity is again twice as large as the _nominal injection quantity valid in full engine operation). From the time t ₁ or from the occurrence of the state change, the cylinder bank B is active, ie the next cylinder to be fired is in this case the cylinder B4. In anticipation of a speed drop, ie depending on the characteristic of the state transition, a new injection target _amount Q _Temp for the firing, s. above too 12 , determined and provided as Q _Soll ^Res for the firing of the cylinder B4. The determination is based on the weighting of the previously applied injection _{target quantity} Q _Soll ^Res = Q _ZA ^stat with the factor f _zyl , wherein the currently valid injection _{target quantity} is increased by weighting with the factor f _zyl at the time t ₃ , ie f _cyl is greater in this case as 1: f _cyl > 1

At time t ₄ , the _target injection quantity Q _Soll ^Res = Q _{Temp is} lowered again to the original level Q _ZA ^stat , so that the next cylinder B5 to be fired is again charged with the original injection _target quantity Q _ZA ^stat .

Diagram c) shows, dotted, the original course of the engine speed accordingly 7 which results without the invention. The continuous course of the engine speed results in contrast, when the injection target amount of the cylinder B4 is raised according to the invention. It can be seen that the engine speed is again smoothed by this measure.

In order to dampen the disturbances of the engine speed - in the sense of smoothing - according to the invention, therefore, an influencing of the injection quantity of at least the first cylinder, which follows directly in the firing order on the change of Zylinderabschalt characteristic.

LIST OF REFERENCE NUMBERS

1

Internal combustion engine

3

front engine half

5

rear engine half

7

Speed control loop

9

regulator

11

limiter

13

engine management

15

Speed filter

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 102012025019 [0045]

Cited non-patent literature

• DIN ISO 8528-5 [0014]

Claims (10)

Method for execution with an internal combustion engine set up for a cylinder deactivation operation ( 1 ), wherein the internal combustion engine ( 1 ) has a plurality of cylinders (A1... B8) and is set up to fire the cylinders (A1... B8) as a function of a respectively current cylinder deactivation characteristic, characterized in that - in a first operating state with a first cylinder deactivation Characteristic, the cylinders to be fired (A1 ... B8) corresponding to a predetermined injection _target amount (Q _target ) are fired according to the first cylinder cut-off characteristic; In a state transition from the first operating state to a second operating state with a second cylinder deactivation characteristic, in which the cylinders (A1... B8) are fired in accordance with a predetermined injection _target quantity (Q _target ) according to the second cylinder deactivation characteristic, at least the first cylinder (A1 ... B8), which is to be fired after the state transition, corresponding to a determined in dependence on a characteristic of the state transition individual injection _{target quantity} (Q _Temp ) for smoothing the state transition due to disturbed speed curve is fired; and subsequently, in the second operating state, the cylinders to be fired (A1... B8) corresponding to the predetermined _target injection quantity (Q _target ) are fired in accordance with the second cylinder deactivation characteristic. A method according to claim 1, characterized in that - in a state transition characteristic, which state transition expected to expect a speed increase, the individual injection _target amount (Q _Temp ) is compared to the predetermined _target injection _setpoint (Q _target ) of the first operating state reduced injection _{target amount} . Method according to one of the preceding claims, characterized in that - in a state transition characteristic, which state transition expected to expect a speed drop, the individual injection _target amount (Q _Temp ) is compared to the _desired injection rate (Q _Soll ) of the first operating state larger injection _target . Method according to one of the preceding claims, characterized in that - the firing with the individual injection _{target quantity} (Q _Temp ) at least for the duration of the disturbance and / or for the first two cylinders (A1 ... B8), which after the state transition to fire are done. Method according to one of the preceding claims, characterized in that - the individual injection _target quantity (Q _Temp ) is determined based on a valid before the state transition predetermined injection _target quantity (Q _Soll ); and / or - the predetermined injection _{setpoint quantity} (Q _setpoint ), which is valid before the state transition, is weighted with a weighting factor (f _zyl ) in the context of the determination of the individual injection _{setpoint quantity} (Q _Temp ). A method according to claim 5, characterized in that - the weighting factor (f _cyl ) at a state transition characteristic, which state transition expectation a speed increase is expected to be less than 1 is selected; and / or - the weighting factor (f _cyl ) is selected to be greater than 1 in the case of a state transition characteristic which, due to the state transition, causes a drop in rotational speed to be expected. Method according to one of claims 5 and 6, characterized in that - the weighting factor is selected as a constant or as a function of the load. Method according to one of the preceding claims, characterized in that - the method in a stationary operation of the internal combustion engine ( 1 ) is performed; and / or the state transition during stationary operation of the internal combustion engine ( 1 ) he follows. Internal combustion engine ( 1 ) with a plurality of cylinders (A1 ... B8), wherein the internal combustion engine ( 1 ) is set up for a cylinder deactivation operation, characterized in that - the internal combustion engine ( 1 ) is arranged to carry out the method according to one of the preceding claims. A computer program product, marked by Program code for carrying out the method according to one of Claims 1 to 8.

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