Internal combustion engine

Abstract

An internal combustion engine comprising: a plurality of cylinders in which combustion chambers are provided, wherein an ignition device and/or a fuel introduction device is associated with each combustion chamber, wherein the combustion chambers are adapted for cyclic ignition of fuel, an open-loop or closed-loop control device for actuation or closed-loop control of the ignition devices and/or fuel introduction devices, and at least one measuring device for detecting a temperature which is characteristic for each cylinder, wherein the open-loop or closed-loop control device is adapted for actuation or closed-loop control of the ignition devices or the fuel introduction devices in dependence on the signals of the at least one measuring device so that no ignition takes place in at least one selected cylinder during at least one cycle and that an even temperature distribution over all cylinders is achieved.

Claims

1. An internal combustion engine comprising: a plurality of cylinders including combustion chambers, wherein an ignition device or a fuel introduction device is associated with each of the combustion chambers, wherein the combustion chambers are adapted for cyclic ignition of fuel, an open-loop or closed-loop control device for actuation or closed-loop control of the ignition devices or the fuel introduction devices, and a plurality of measuring devices, each for detecting a temperature which is characteristic for one of the cylinders, wherein the open-loop or closed-loop control device is adapted for actuation or closed-loop control of the ignition devices or the fuel introduction devices in dependence on signals of the measuring devices such that (i) the ignition device or the fuel introduction device associated with at least one of the cylinders is inactive during at least one cycle in a situation in which the characteristic temperature of at least one of the cylinders reaches or exceeds a predeterminable upper value for actuation or closed-loop control of the at least one of the cylinders, and (ii) the ignition device or the fuel introduction device associated with at least one of the cylinders is active in a situation in which the characteristic temperature of the at least one of the cylinders reaches or falls below a predeterminable lower value for actuation or closed-loop control of the at least one of the cylinders, whereby an even temperature distribution over all of the cylinders is achieved, and wherein the predeterminable upper value or the predeterminable lower value is established based on an average temperature of all of the cylinders.

2. The internal combustion engine as set forth in claim 1, wherein the fuel introduction devices are port injection valves.

3. The internal combustion engine as set forth in claim 1, wherein the fuel introduction devices are variable inlet valves of a variable valve gear.

4. The internal combustion engine as set forth in claim 1, wherein the fuel introduction devices are injectors arranged directly in the cylinders, respectively.

5. The internal combustion engine as set forth in claim 1, wherein the ignition devices are spark ignition devices, corona ignition devices, glow plugs or laser ignition devices.

6. The internal combustion engine as set forth in claim 1, wherein a baseline pattern is stored in an electronic memory of the open-loop or closed-loop control device, in accordance with which the ignition devices or the fuel introduction devices are actuable or regulatable by the open-loop or closed-loop control device in such a way that the ignition device or the fuel introduction device associated with the at least one of the cylinders is inactive during the at least one cycle, and wherein the open-loop or closed-loop control device is adapted, in a first operating mode, for actuation or closed-loop control of the ignition devices or the fuel introduction devices in accordance with the baseline pattern, without taking into account the signals of the measuring devices.

7. The internal combustion engine as set forth in claim 1, wherein, in addition to the signals of the measuring devices, further signals which are characteristic for a rotary speed and a load presetting to the internal combustion engine are fed to the open-loop or closed-loop control device and the open-loop or closed-loop control device is adapted, in dependence on the further signals, to establish what proportion of all of the ignition devices or the fuel introduction devices are active.

8. The internal combustion engine as set forth in claim 1, wherein the open-loop or closed-loop control device is adapted, in the event of failure of one of the signals of the measuring devices, for actuation or closed-loop control of the ignition devices or the fuel introduction devices corresponding to a predetermined number of past cycles.

9. A method of operating an internal combustion engine having a plurality of cylinders including combustion chambers, wherein an ignition device or a fuel introduction device is associated with each of the combustion chambers, wherein the combustion chambers are adapted for cyclic ignition of fuel, the internal combustion engine having an open-loop or closed-loop control device for actuation or closed-loop control of the ignition devices or the fuel introduction devices, and a plurality of measuring devices, each for detecting a temperature which is characteristic for one of the cylinders, wherein the open-loop or closed-loop control device is adapted for actuation or closed-loop control of the ignition devices or the fuel introduction devices in dependence on signals of the measuring devices such that (i) the ignition device or the fuel introduction device associated with at least one of the cylinders is inactive during at least one cycle in a situation in which the characteristic temperature of the at least one of the cylinders reaches or exceeds a predeterminable upper value for actuation or closed-loop control of the at least one of the cylinders, and (ii) the ignition device or the fuel introduction device associated with at least one of the cylinders is active in a situation in which the characteristic temperature of the at least one of the cylinders reaches or falls below a predeterminable lower value for actuation or closed-loop control of the at least one of the cylinders, whereby an even temperature distribution over all of the cylinders is achieved, and wherein the predeterminable upper value or the predeterminable lower value is established based on an average temperature of all of the cylinders.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details and advantages of the invention will be apparent from the Figures and the related specific description.

(2) FIG. 1 diagrammatically shows the circuit diagram and line diagram of an internal combustion engine 1. The internal combustion engine 1 has a plurality of cylinders 2 which can be supplied with fuel by way of fuel introduction devices 4. For the sake of clarity of the drawing, only three cylinders 2 are shown. By way of the temperature signal line S3, the open-loop or closed-loop control device 5 receives signals from the sensors 6 of the measuring device for determining the characteristic temperature of the cylinders 2, information relating to the characteristic temperature of the cylinders 2, and also by way of the signal line S2, signals which are characteristic of the power and speed of the internal combustion engine 1.

(3) Ignition devices 3 are not shown in FIG. 1, but can obviously be present. The open-loop or closed-loop control device 5 can send commands for the introduction of fuel to the fuel introduction devices 4 by way of the fuel feed signal line S1. The fuel feed is effected by way of the fuel feed line G. The feed of air is effected separately here through the air feed line L.

(4) This embodiment is relevant, for example, for internal combustion engines which are equipped with a port-injection system or a variable valve gear.

(5) FIG. 2 diagrammatically shows the circuit diagram and line diagram of an internal combustion engine 1 as shown in FIG. 1, wherein ignition devices 3 are shown. As described in FIG. 1, the open-loop or closed-loop control device 5 receives signals from the sensors 2 of the measuring device for determining the characteristic temperature of the cylinders 2 and also further signals from further sensors (not shown) which are characteristic of the power output and speed of the internal combustion engine 1. The open-loop or closed-loop control device 5 can pass commands for ignition or non-ignition to the ignition devices by way of the ignition signal line S4.

(6) FIG. 3 diagrammatically shows the circuit diagram and line diagram of an internal combustion engine 1, showing ignition devices 3 and fuel introduction devices 4. Here, therefore, there is the possibility of the ignition devices 3 and fuel introduction devices 4 being actuated separately by means of an ignition signal line S4 and a fuel feed signal line S1, respectively.

(7) FIG. 4 shows a diagram, time being shown on the X-axis thereof. The Y-axis is interrupted and in the upper part shows the characteristic temperature in any units for each of the cylinders 2 of which five are shown as an example. The five cylinders 2 selected by way of example can be distinguished therein by references Z1 through Z5 and are clearly identified thereby.

(8) FIG. 5 shows a graph, time (t) being shown on the X-axis and on the Y-axis temperature (T) in any units for each of the cylinders 2 of which five are shown as an example (references Z1 through Z5).

(9) FIG. 6 shows a graph, time (t) being shown on the X-axis and on the Y-axis temperature (T) in any units for each of the cylinders 2 of which five are shown as an example (references Z1 through Z5).

DETAILED DESCRIPTION OF THE INVENTION

(10) In addition, the ignition status for each of the five cylinders 2 Z1 through Z5 is also shown on the Y-axis, wherein a ‘1’ signifies that the cylinder 2 in question experiences ignition in a cycle and a ‘0’ signifies that there is no ignition in a cycle.

(11) A separate plotting beneath the X-axis represents the number of cylinders 2 which are not to experience ignition (established by the open-loop or closed-loop control device 5 in dependence on the power and/or speed requirement of the internal combustion engine 1) in dependence on the time identified on the X-axis. It will be seen that up to the time t1 no cylinders are omitted (zero) and from time t1 two cylinders are intended for non-ignition (illustrated by the number 2).

(12) At time t1, the command for non-ignition is given by the open-loop or closed-loop control device 5. In the present case, this means that the fuel introduction devices 4 of the selected cylinders 2 (in the present case, cylinders No. 1 and No. 4) are not activated so that no fuel is introduced into those cylinders 2 and thus those cylinders 2 do not have ignition in the following cycle. The presetting for non-ignition of two cylinders therefore corresponds to the setting of a baseline pattern which, for example, reflects the currently prevailing power demand on the internal combustion engine 1.

(13) After the time t1, the decision for non-ignition or ignition of the cylinders 2 is no longer implemented by presetting of the baseline pattern, but in dependence on the characteristic temperature of the cylinders 2, that is ascertained by the sensors 6.

(14) Now, implementation of skip firing in dependence on the characteristic temperature of the individual cylinders 2 is to be described by means of the example in FIG. 4:

(15) Firstly, at the time t2, the cylinder identified by the number Z4 falls below the lower limit of the characteristic temperature UL and is therefore intended for ignition in the next cycle by the open-loop or closed-loop control device 5. At the same time, the cylinder identified by the number Z2 is at the highest characteristic temperature, reaches the upper temperature limit OL and therefore does not have ignition in the next cycle; next, the cylinder Z1 reaches the lower limit UL and is therefore intended for ignition in the next cycle and so forth.

(16) It can be clearly seen that, in the selected example, by virtue of the omission of two cylinders 2, the mean of the characteristic temperatures M falls in relation to the condition of complete ignition, that is to say no cylinder 2 is omitted.

(17) The illustrated number of five cylinders 2 is selected only by way of example, in reality, it is possible to provide any number of cylinders, in practice generally between 12 and 24.

(18) FIG. 5, in a diagram similar to FIG. 4, illustrates the situation where, at the time t2, the transition takes place from two cylinders intended for omission (non-ignition) to only one cylinder which is not to involve ignition. It may be necessary, for example, due to an increased power demand, to add a cylinder 2. That cylinder 2 is activated for ignition, that is at the lowest characteristic temperature, in the illustrated example this being the cylinder 2 identified by number Z4. The number of cylinders intended for omission is again shown in a separate graph below the main axis. It will be seen therein that, at the time t2, the status jumps from two cylinders intended for omission to one.

(19) FIG. 6 shows a diagram similar to FIG. 5 for the situation where, at the time t2, the transition occurs from two cylinders 2 to three cylinders 2 which are intended for omission (non-ignition). It may be necessary, for example, due to a reduced power demand, to omit a further cylinder 2. That cylinder 2 is deactivated from ignition, that is at the highest characteristic temperature, in the illustrated example this being the cylinder 2 No. 3. Illustrated in a separate graph beneath the main axis is the fact that, at the time t3, the status jumps from two non-ignition cylinders to three non-ignition cylinders.

(20) Internal combustion engines according to the invention are preferably in the form of, in particular, stationary engines (preferably gas Otto-cycle engines) which are particularly preferably coupled to an electric generator for power generation.

LIST OF REFERENCES USED

(21) 1 internal combustion engine 2 cylinder 3 ignition device 4 fuel introduction device 5 open-loop or closed-loop control device 6 sensors of the measuring device for determining the characteristic temperature G fuel feed line L air feed line S1 fuel feed signal line S2 engine signal line S3 temperature signal line S4 signal line T temperature t time M mean temperature OL upper temperature limit UL lower temperature limit Z1-Zi identification of selected cylinders