EP2955355A1 - Combustion engine with skip-firing - Google Patents

Abstract

Internal combustion engine (1) with: - A plurality of cylinders (2) in which combustion chambers are formed, wherein each combustion chamber is associated with an ignition device (3) and / or a fuel introduction device (4), wherein the combustion chambers are formed for the cyclical ignition of fuel, - A control or regulating device (5) for controlling or regulating the ignition devices (3) and / or fuel introduction devices (4) and at least one measuring device (6) for detecting a characteristic temperature for each cylinder (2), wherein the control or regulating device (5) is designed to control or regulate the ignition devices (3) and / or fuel introduction devices (4) in dependence on the signals of the at least one measuring device (6) in at least one selected cylinder (2 ) During at least one cycle no ignition takes place and sets a uniform temperature distribution over all cylinders (2).

Description

The present invention relates to an internal combustion engine having the features of the preamble of claim 1 and a method for operating an internal combustion engine having the features of the preamble of claim 15.

The individual combustion chambers of the internal combustion engine are designed as piston-cylinder units (often referred to as cylinders for short). Depending on the type of internal combustion engine, a subdivision of the combustion chambers in antechamber and main combustion chambers can be provided. In this case, the ignition device is usually assigned to the antechamber.

For various reasons, it may be desirable to selectively shut off cylinders of the internal combustion engine at least temporarily, which in the context of the present application is to be understood as meaning that the respective ignition device and / or fuel introduction device remains inactive.

Method for cylinder shutdown, "Skip firing", are known from the prior art. Cylinder deactivation is primarily used on larger engines with more than 6 cylinders to reduce fuel consumption and emissions with reduced power demand.

In the DE 43 10 261 For example, it is described that to protect against overloading of an engine, patterns for selective cylinder deactivation (called skip patterns in the text) can be specified.

The patterns are advantageously matched to the number of cylinders so that circumferential Ausblendsequenzen result, d. H. within a very short time each cylinder is relieved.

From the DE 2928075 It is also known that the sequence of commands for ignition and cylinder deactivation is selected so that the internal combustion engine runs as smoothly as possible, in particular harmonics of the resonance frequencies of the engine mount and the drive train are avoided.

In the US patent application US 20130289853 A method of cylinder deactivation is described in which ignition instructions are stored in a look-up table and the entry for the next ignition command is determined by means of a counter in the look-up table.

The object of the invention is to provide an internal combustion engine and a method for operating an internal combustion engine, in which or in which excessive mechanical loads or wear by skip firing are avoided.

This object is achieved by an internal combustion engine having the features of claim 1 and a method having the features of claim 15. Advantageous embodiments of the invention are specified in the dependent claims.

• Ein thermisch gleichmäßigerer Zustand führt zu geringerer mechanischer Belastung und zu geringerem Verschleiß der Brennkraftmaschine. Der Schmiermittelhaushalt wird verbessert, da ein geringerer Wärmeeintrag in den Schmiermittelkreis erfolgt.

Characterized in that the control or regulating device is adapted to control or regulate the ignition devices and / or fuel introduction devices in response to the signals of the at least one measuring device for detecting a temperature characteristic of each cylinder, that in at least one selected cylinder during at least one cycle Ignition occurs, a more uniform thermal state of the internal combustion engine can be achieved. This brings several advantages:

• A thermally more uniform state leads to less mechanical stress and less wear of the internal combustion engine. The lubricant balance is improved because there is less heat input into the lubricant circuit.

In the present disclosure, "fuel" is understood to mean either pure fuel, such as fuel gas, or a fuel-air mixture. "Cycle" is understood to mean a working cycle of the engine, that is to say in the case of a four-stroke engine a crankshaft rotation of 720 °, in the case of a two-stroke engine a crankshaft rotation of 360 °, 360 ° corresponding to a full angle.

In the context of the present application, "ignition" also means "ignition", ie when "no ignition takes place in one cycle", it is to be understood that in this cycle the mixture does not ignite, ie that the respective ignition device and / or Fuel introduction device remains inactive.

The characteristic temperature may be, for example, an exhaust gas temperature, a temperature in the cylinder itself, a temperature of a connecting rod bearing or of individual parts of the cylinder (for example cylinder head, fire plate, piston or liner). The sensors are to be arranged accordingly in the internal combustion engine, as is familiar to the expert.

Preferably, it can be provided that the control or regulating device is designed to control or regulate the fuel introduction device of the at least one selected cylinder during the at least one cycle so that the introduction of fuel into the at least one selected cylinder is interrupted. In this case, a possibly provided ignition device can remain active or switched on, since in any case no ignitable fuel is present in the combustion chamber.

Additionally or alternatively, it can be provided that the control or regulating device is designed to switch off or not to activate the ignition device of the at least one selected cylinder during the at least one cycle. In this case, it may even be provided that a possibly provided fuel introduction device remains active or switched on, since fuel in the combustion chamber is not ignited.

The fuel introduction devices may be designed, for example, as port injection valves, as variable intake valves of a variable valve train or as in-cylinder injectors. The injectors can be designed for the direct injection of fuel in an Otto engine or for the injection of diesel in a diesel engine.

The ignition devices - if they are present - can be designed, for example, as spark ignition devices, corona ignition devices, glow plugs or as laser ignition devices.

In a further preferred embodiment of the invention it is provided that an output pattern is stored in an electronic memory of the control or regulating device, according to which the ignition devices and / or fuel introduction devices by the control or regulating device so can be controlled or regulated that in at least one selected cylinder during at least one cycle, no ignition, wherein the control or regulating device is adapted to, in a first operating mode, the ignition device and / or fuel introduction devices without taking into account the signals of the at least one measuring device according to the output pattern to control or regulate. The output pattern may be chosen so that the sequence of firings or omissions results in the most even distribution possible of the mechanical and thermal load on the engine, as already known from the prior art. The output pattern for the cylinder deactivation can be matched to the current power requirement of the internal combustion engine.

It is particularly preferred that the control or regulating device is designed, in the event that the characteristic temperature of at least one of the cylinders reaches or exceeds a predeterminable upper value, to control or regulate this cylinder so that no ignition takes place. In the event that an initial pattern is used in a first operating mode as described above, this measure can be provided as a second operating mode in which the first operating mode is changed. This ensures that a cylinder with a particularly high characteristic temperature is excluded from the ignition, thereby reducing the thermal load on the corresponding cylinder.

It is particularly preferred that the control or regulating device is designed, in the event that the characteristic temperature of at least one of the cylinders reaches or falls below a predeterminable lower value, to control or regulate this cylinder in such a way that ignition takes place. This measure can be carried out in isolated form or in combination with one of the measures described above. This ensures that a cylinder with a particularly low characteristic temperature is not excluded from the ignition, so from the next cycle so ignites, and thereby the thermal load is increased to the corresponding cylinder.

For example, it may also be provided that the upper and / or lower value is determined based on the average temperature of all cylinders (or in a variant only selected ones, for example only those cylinders of a cylinder bank).

The average temperature can be determined by the arithmetic mean or median. The upper and lower limits are calculated from the average temperature and an offset. The offset can be chosen differently, depending on how many cylinders are intended for non-ignition. The offset thus corresponds to the band deviation from the average temperature over which the affected cylinder receives the command for non-ignition or under which the affected cylinder receives the command to ignite. To illustrate this with a numerical example: the average temperature of the temperatures determined directly at the outlet valve is 350 ° C, the offset is selected to be 100 ° C. Then, the upper limit at which the affected cylinder receives the non-ignition command is 450 ° C. The lower limit at which the affected cylinder receives the command to ignite is then 250 ° C. The offset thus determines how wide the band is in which the individual cylinder temperatures may be before their ignition status is changed. It may be narrower, for example, 30-40 ° C, which has many control actions on the ignition status of the cylinders. With a wider choice of the band, so by a larger offset, the cylinder temperatures may vary more widely. The aim of the measure, however, is to keep the cylinder temperatures in the narrowest possible band, ie to achieve a uniform temperature distribution over all cylinders. In practice, the offset would be chosen asymmetrically with respect to the average temperature, i. For example, the lower offset, which defines the lower temperature limit of a cylinder, is chosen to be greater in magnitude than the upper offset, which defines the upper temperature limit of a cylinder.

It is particularly preferred that the control or regulating device in addition to the signals of the measuring device also further, for the speed and / or load specification of the internal combustion engine signals are fed and the control or regulating device is adapted to set in dependence of the further signals, which proportion of the total existing cylinder comes to the ignition. This takes into account that the omission of cylinders should, of course, only to an extent that is adapted to the current load or speed requirement to the engine. This means, for example, that at full load of the internal combustion engine should not be ignored.

For example, if the demand for maintaining a speed requires a higher number of ignited cylinders per cycle than currently provided, such cylinders are preferably controlled or controlled to be ignited by the controller, which has a lower characteristic compared to the other cylinders Have temperature.

For example, if the specification for maintaining a speed requires a lower number of ignited cylinders per cycle than currently provided, those cylinders are preferably added to the ignition having a higher characteristic temperature compared to the other cylinders.

Particularly preferably, it is provided that the control or regulating device is designed to control or regulate this cylinder with respect to its ignition according to a predetermined number of past cycles in case of failure of a signal characteristic of a cylinder temperature. This ensures that in case of failure of a sensor, the corresponding cylinder is fired according to the past cycles.

The upper and / or lower limit may be set based on the average temperature of all or selected cylinders. The average temperature can be determined by the arithmetic mean or median. Subgroups can be formed, for example, one cylinder bank each, to which the algorithm is applied.

As a method it is provided that the deactivation of at least one cylinder takes place as a function of the characteristic temperature of that at least one cylinder. The possibilities of the embodiment explained with regard to the device apply.

Further details and advantages of the invention will become apparent from the figures and the associated description of the figures.

FIG. 1 schematically shows the circuit diagram and wiring diagram of an internal combustion engine 1. The internal combustion engine 1 has a plurality of cylinders 2, which can be supplied via fuel introduction devices 4 with fuel. For the sake of clarity, only three cylinders 2 are shown. The tax or Control device 5 receives via the temperature signal line S3 signals from the sensors 6 of the measuring device for determining the characteristic temperature of the cylinder 2 information on the characteristic temperature of the cylinder 2, and also via the signal line S2 signals that are characteristic of the power and speed of the internal combustion engine 1 are.

In FIG. 1 Ignition devices 3 may be present, of course. The control device 5 may provide commands for introducing fuel to the fuel injectors 4 via the fuel supply signal line S1. The fuel is supplied via the fuel supply line G. The air supply takes place here separately through the air supply line L.

This embodiment is relevant to, for example, an internal combustion engine equipped with a port injection injection or a variable valve train.

FIG. 2 schematically shows the circuit diagram and wiring diagram of an internal combustion engine 1 according to FIG. 1 , wherein ignition devices 3 are shown. As in FIG. 1 described, receives the control or regulating device 5 signals from the sensors 6 of the measuring device for determining the characteristic temperature of the cylinder 2 and also other signals from other sensors (not shown), which are characteristic of the power and speed of the internal combustion engine 1. The control or regulating device 5 can pass the ignition devices 3 via the ignition signal line S4 commands for ignition or non-ignition.

FIG. 3 schematically shows the circuit diagram and line diagram of an internal combustion engine 1, wherein ignition devices 3 and fuel introduction devices 4 are shown. Here, therefore, the possibility is given to separately control the ignition devices 3 and fuel introduction devices 4 by means of ignition signal line S4 or fuel supply signal line S1.

FIG. 4 shows a diagram on the X-axis time is shown. The Y-axis is broken and shows in the upper part for each of the exemplary five illustrated cylinder 2, the characteristic temperature in any units. The five Cylinder 2 selected by way of example can be distinguished and identified therein by the designations Z1 to Z5.

In addition, the ignition status for each of the five cylinders 2 Z1 to Z5 is shown on the Y axis, where a "1" means that the relevant cylinder 2 is ignited in one cycle and a "0" means that it is not fired in one cycle becomes.

In a separate plot below the X-axis, the number of cylinders 2 not to be ignited (set by the controller 5 as a function of the power and / or speed requirement of the engine 1) is dependent on that on the X-axis Plotted time shown. It can be seen that no cylinders are skipped (zero) until time t1, and two cylinders (represented by the number 2) are provided for non-ignition as of time t1.

At time t1, the command for non-ignition is given by the controller 5. In the present case, this means that the fuel introduction devices 4 of the selected cylinders 2 (in the present case, the cylinders No. 1 and No. 4) are not activated, so that no fuel is introduced into these cylinders 2, and thus these cylinders 2 in the subsequent cycle do not ignite. The specification for non-ignition of two cylinders thus corresponds to the specification of the output pattern, which, for example, reflects the current power requirement on the internal combustion engine 1.

• Zunächst unterschreitet Zylinder mit der Nummer Z4 bei der Zeit t2 die untere Grenze der charakteristischen Temperatur UL und wird von der Steuer- oder Regeleinrichtung 5 daher zur Zündung im nächsten Zyklus vorgesehen. Zeitgleich weist der Zylinder mit der Nummer Z2 die höchste charakteristische Temperatur auf, erreicht das obere Temperaturlimit OL und wird daher beim nächsten Zyklus nicht gezündet; als nächstes erreicht Zylinder Z1 das untere Limit UL und wird daher zur Zündung im nächsten Zyklus vorgesehen usw.

After the time t1, the decision to ignite or ignite the cylinder 2 is no longer made by specifying the output pattern, but in dependence of the determined by the sensors 6 characteristic temperature of the cylinder 2. Now, the end of the cylinder shutdown in dependence of the characteristic temperature of the individual cylinders 2 using the example of FIG. 4 be explained:

• Initially, cylinder numbered Z4 falls short of the lower limit of the characteristic temperature UL at time t2, and is therefore provided by the controller 5 for ignition in the next cycle. At the same time, the cylinder with the number Z2 has the highest characteristic temperature, reaches the upper temperature limit OL and is therefore not ignited in the next cycle; Next, cylinder Z1 reaches the lower limit UL and is therefore scheduled for ignition in the next cycle, and so on.

It will be appreciated that in the example chosen, by omitting two cylinders 2, the mean of the characteristic temperatures M versus the state of complete ignition, i. no cylinder 2 is skipped, sinks.

The shown number of five cylinders 2 is chosen only as an example, in reality any number of cylinders can be provided, in practice usually between 12 and 24.

FIG. 5 shows in a diagram analogous to FIG. 4 the case that at time t2 the transition from two cylinders intended for omission (non-ignition) takes place to only one cylinder which is not to be ignited. For example, it may be necessary to add a cylinder 2 due to increased load demand. It is switched on that cylinder 2 to the ignition, which has the lowest characteristic temperature, in the example shown, this is the cylinder 2 with number Z4. The number of omission cylinders is again shown in a separate graph below the major axis. It can be seen that at time t2 the status of two cylinders intended for omission jumps to one.

FIG. 6 shows a diagram analogous to FIG. 5 the case that at time t3, the transition from two to three provided for deletion (non-ignition) cylinders 2 takes place. It may be necessary, for example by reduced load request, to exclude another cylinder 2. The cylinder 2 is switched away from the ignition which has the highest characteristic temperature, in the example shown this is the cylinder 2 with No. 3. Below the main axis is illustrated in a separate graph that at time t3 the status of two non- ignited cylinders on three un-fired cylinders.

Internal combustion engines according to the invention are preferably designed as in particular stationary engines (preferably gas Otto engines), which are particularly preferably coupled to an electric generator for power generation.

List of reference numbers used:

1

Internal combustion engine

2

cylinder

3

ignition device

4

Fuel delivery device

5

Control or regulating device

6

Sensors of the measuring device for determining the characteristic temperature

G

Fuel supply line

L

Air supply line

S1

Fuel supply signal line

S2

Motor signal line

S3

Temperature signal line

S4

signal line

T

temperature

t

Time

M

Medium temperature

OIL

Upper temperature limit

UL

Lower temperature limit

Z1-Zi

Marking of selected cylinders

Claims (15)

Internal combustion engine (1) with: - A plurality of cylinders (2) in which combustion chambers are formed, wherein each combustion chamber is associated with an ignition device (3) and / or a fuel introduction device (4), wherein the combustion chambers are formed for the cyclical ignition of fuel, - A control or regulating device (5) for controlling or regulating the ignition devices (3) and / or fuel introduction devices (4) and at least one measuring device (6) for detecting a characteristic temperature for each cylinder (2), characterized in that
the control or regulating device (5) is designed to control or regulate the ignition devices (3) and / or fuel introduction devices (4) as a function of the signals of the at least one measuring device (6) in at least one selected cylinder (2). during at least one cycle no ignition takes place and sets a uniform temperature distribution over all cylinder (2). Internal combustion engine (1) according to claim 1, characterized in that the control device (5) is adapted to control or regulate the fuel introduction device (4) of the at least one selected cylinder (2) during the at least one cycle such that the Introduction of fuel into the at least one selected cylinder (2) is interrupted. Internal combustion engine (1) according to claim 1 or 2, characterized in that the control or regulating device (5) is adapted to switch off the ignition device (3) of the at least one selected cylinder (2) during the at least one cycle or not. Internal combustion engine (1) according to at least one of claims 1 to 3, characterized in that the fuel introduction devices (4) are designed as port injection valves. Internal combustion engine (1) according to at least one of claims 1 to 3, characterized in that the fuel introduction devices (4) are designed as variable intake valves of a variable valve train. Internal combustion engine (1) according to at least one of claims 1 to 3, characterized in that the fuel introduction devices (4) are designed as injectors arranged directly in the cylinder. Internal combustion engine (1) according to at least one of claims 1 to 6, characterized in that the ignition devices (3) are designed as spark ignition devices, corona ignition devices, glow plugs or laser ignition devices. Internal combustion engine (1) according to at least one of claims 1 to 7, characterized in that in an electronic memory of the control or regulating device (5) an output pattern is stored, after which the ignition devices (3) and / or fuel introduction devices (4) through the Control or regulating device (5) are controlled or regulated so that in at least one selected cylinder (2) during at least one cycle, no ignition, wherein the control or regulating device (5) is adapted to in a first operating mode, the ignition device ( 3) and / or fuel introduction devices (4) without taking into account the signals of the at least one measuring device (6) according to the output pattern to control or regulate. Internal combustion engine (1) according to at least one of claims 1 to 8, characterized in that the control or regulating device (5) is adapted, in the case that the characteristic temperature of at least one of the cylinders (2) reaches or exceeds a predetermined upper value to control or regulate this cylinder (2) so that no ignition takes place. Internal combustion engine (1) according to at least one of claims 1 to 9, characterized in that the control or regulating device (5) is designed, in the event that the characteristic temperature of at least one of Cylinder (2) reaches a predetermined lower value or falls below this cylinder (2) to control or regulate that an ignition takes place. Internal combustion engine (1) according to claim 9 and / or 10, characterized in that the upper and / or lower value is determined based on the average temperature of all cylinders (2). Internal combustion engine (1) according to at least one of claims 1 to 11, characterized in that the control or regulating device (5) in addition to the signals of the measuring device (6) also further, for the speed and / or load specification of the internal combustion engine (1) characteristic Signals are supplied and the control or regulating device (5) is adapted to determine depending on the further signals, which share of the total existing cylinder (2) comes to the ignition. Internal combustion engine (1) according to at least one of claims 1 to 12, characterized in that the control or regulating device (5) is designed, in case of failure of a signal characteristic of a cylinder (2) temperature of this cylinder (2) with respect to its ignition according to a predetermined number of past cycles to control or regulate. Internal combustion engine (1) according to at least one of claims 9 to 13, characterized in that the upper and / or lower value is determined based on the average temperature of all or selected cylinders (2). Method for operating an internal combustion engine (1) having a multiplicity of cylinders (2) in which combustion chambers are formed, wherein each combustion chamber is assigned an ignition device (3) and / or a fuel introduction device (4), the combustion chambers for the cyclical ignition of fuel are formed, with a control or regulating device (5) for driving or controlling the igniters (3) and / or fuel supply devices (4) and at least one measuring means (6) for detecting for each cylinder (2) characteristic temperature, characterized in that that the control or regulating device (5) the Ignition devices (3) and / or fuel introduction devices (4) depending on the signals of the at least one measuring device (6) controls or regulates that in at least one selected cylinder (2) during at least one cycle no ignition takes place and a uniform temperature distribution over all Cylinder (2) sets.

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