Method for controlling and/or regulating the operation of an internal combustion engine

Abstract

A method for controlling and/or regulating the operation of an internal combustion engine, wherein the relevant specific relative locations of the intake camshaft with respect to the crankshaft are defined and/or controlled with the aid of regulating control values of the engine control unit, in particular for controlling the intake valves between the control value 1 for late and the control value 0 for early, and wherein a specific regulating control value curve and/or specific regulating control values for controlling the relative position of the intake camshaft is or are stored, at least for a specific control period for implementing the load jump, namely at least between the time of the start of the target load jump to the time of the end of the actual load jump corresponding to the target load jump.

Claims

1. A method for controlling or regulating an operation of an internal combustion engine, the method comprising: applying multiple different target load points from an actuation of the accelerator pedal to the internal combustion engine, wherein in a case of a load increase of the internal combustion engine starting from at least one specific applied, lower first target load point, a specific, higher, second target load point, compared to a first target load point of the multiple different target load points, is applied; and moving positioning of an intake camshaft with respect to a crankshaft in order to control intake valves, a relevant control of the intake valves from early to late being implemented through a relative position of an intake camshaft, wherein relevant specific relative locations of the intake camshaft with respect to the crankshaft are controlled with by regulating control values of the engine control unit to control the intake valves between the control value 1 for late and the control value 0 for early, and wherein at least for a specific control period for implementing the load increase, and specific regulating control values for controlling the relative position of the intake camshaft are stored, wherein, at least for the specific control period, specific regulating control limit values are defined, wherein, then at specific relevant times within the specific control period a comparison of the relevant regulating control values with the relevant regulating control limit values takes place, and wherein a relevant lower control value is then used to drive a relative location of the intake camshaft.

2. The method according to claim 1, wherein, through a use of the relevant lower control value, a movement of the intake camshaft in the late direction is appropriately limited to this corresponding value or control value.

3. The method according to claim 1, wherein, during the specific control period, relevant specific stationary regulating control limit values are defined for multiple specific relevant actual load points.

4. The method according to claim 1, wherein the specific regulating control limit values have been determined for stationary actual load points on a test stand for stationary specific actual load conditions.

5. The method according to claim 1, wherein the specific regulating control limit values are stored in the engine control unit as a characteristic map or as a stationary regulating control limit curve.

6. The method according to claim 1, wherein, with aid from the relevant specific regulating control limit values dynamic regulating control limit values are determined as a function of a combustion chamber heating.

7. The method according to claim 6, wherein the relevant dynamic regulating control limit values are used as the relevant regulating control limit values in a comparison.

8. The method according to claim 1, wherein the pressure in the intake system is at least partially controlled by an exhaust-gas turbocharger.

9. The method according to claim 1, wherein relevant characteristic delay times are determined on a test stand, wherein the relevant values of characteristic delay times then each correspond to a relevant delay time until the internal combustion engine has reached its new heating state.

10. The method according to claim 1, wherein the internal combustion engine is an Otto engine.

11. The method according to claim 1, wherein a control or regulating circuit is provided that has at least one first circuit element designed as a comparing element and at least one second circuit element designed as a time delay element.

12. The method according to claim 11, wherein the regulating control values that are stored in the engine control unit by the engine control unit are routed to the first circuit element through a first control path.

13. The method according to claim 12, wherein a second control path is provided that has two sub-paths, wherein a stationary regulating control limit value is routed to the second circuit element through a first sub-path of the two sub-paths, and a value for a characteristic delay time for a combustion chamber heating is routed through a second sub-path of the two sub-paths.

14. The method according to claim 13, wherein the second circuit element determines a dynamic regulating control limit value based on the value of the characteristic delay time routed to the second circuit element.

15. The method according to claim 14, wherein a comparison is performed by the first circuit element, wherein the dynamic regulating control limit value of the second circuit element is routed to the first circuit element, wherein the relevant lower control value is used for driving the relative location of the intake camshaft.

16. The method according to claim 1, wherein the internal combustion engine is for a motor vehicle and operates at least partially according to a Miller cycle.

17. The method according to claim 1, wherein the multiple different target load points correspond to different actual load points of the internal combustion engine, wherein the at least one specific applied, lower first target load point is a first actual load point implemented for the first target load point, wherein the first target load point is a first actual load point, wherein moving the position involves adjusting a relative location of the intake camshaft with respect to the crankshaft, wherein the at least for a specific control period for implementing the load increase is at least between a first time at the start of the target load increase to a second time at the end of the actual load increase corresponding to the target load increase, wherein a specific regulating control value curve includes the specific regulating control values, and wherein a regulating control limit curve includes the specific regulating control limit values.

18. The method according to claim 1, wherein a dynamic regulating control limit curve is determined from the regulating control limit curve as a function of a curve of a combustion chamber heating.

19. The method according to claim 1, the method further comprising: applying the multiple different target load points from the actuation of the accelerator pedal to different actual load points of the internal combustion engine, wherein the multiple different target load points correspond in time to the different actual load points of the internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

(2) FIG. 1 is a schematic representation of the method according to an exemplary embodiment implemented in an internal combustion engine, in particular a regulating control limit curve and/or specific regulating control limit values for a specific control period, namely for a load jump, in particular for a load increase of the internal combustion engine, and

(3) FIG. 2 is a schematic block diagram of a partial section of the control system for controlling and/or regulating the operation of an internal combustion engine using the method according to the invention.

DETAILED DESCRIPTION

(4) FIGS. 1 and 2 show—at least partially—an exemplary method according to the invention for controlling and/or regulating the operation of an internal combustion engine, in particular of an internal combustion engine of a motor. In this case the internal combustion engine is, in particular, at least partially controlled and/or regulated according to the Miller cycle.

(5) FIG. 1 shows a load jump, namely a load increase of the internal combustion engine, over the course of the time t. In the case of an internal combustion engine, multiple different target load points and/or actual load points of the internal combustion engine can be applied in a known manner, in particular by an appropriate actuation of the accelerator pedal.

(6) FIG. 1 shows here a load jump, namely a load increase of the internal combustion engine to a specific, higher, second target load point LP.sub.Target2 starting from at least one specific applied, lower target load point LP.sub.Target1 and/or starting from a first actual load point LP.sub.Actual1 implemented for the first target load point LP.sub.Target1. In this case, the higher, second target load point LP.sub.Target2 is correspondingly higher or greater compared to the first target load point LP.sub.Target1 or compared to the corresponding actual load point LP.sub.Actual1, as is clearly visible from FIG. 1 and/or as is correspondingly shown by the curve of the line illustrating the load jump. In addition, it is evident from FIG. 1 that the actual load points LP.sub.Actual of the internal combustion engine ramp up during the load jump from LP.sub.Actual1 to LP.sub.Target2/LP.sub.Actual2, in particular ramp up with a corresponding time delay. This is evident from the representation in FIG. 1, in particular the representation of the load points LP on the (upper) y-axis over the time t.

(7) The relative location or relative positioning of an intake camshaft with respect to a crankshaft for controlling intake valves is appropriately movable and/or adjustable. The relevant control of the intake valves from “early” to “late” (or vice versa) can be achieved through the relative position of the intake camshaft, as already explained above. The relevant specific relative locations of the intake camshaft with respect to the crankshaft are first defined and/or controlled fundamentally with the aid of regulating control values of the engine control unit (see also FIG. 2 in this regard). In this process, the regulating control values take on values between the control value “1,” in particular, for a “late” end position, and the control value “0,” in particular, for an “early” end position.

(8) In FIG. 1, the regulating control values RS or the corresponding curve of the regulating control values RS.sub.Curve, which is to say the corresponding regulating control value curve RS.sub.Curve, are represented by the corresponding line. The corresponding regulating control value curve RS.sub.Curve is shown over the time t, wherein, as indicated on the y-axis, the corresponding regulating control value RS, in particular values between “1” and “0” here, should then be shown on the (lower) y-axis.

(9) For a specific control period for implementing the load jump, namely the load increase, namely at least from the time t.sub.1 at the start of the target load jump until the time t.sub.4 at the end of the actual load jump corresponding to the target load jump, a specific regulating control value curve RS.sub.Curve and/or specific regulating control values RS for controlling the relative position of the intake camshaft are stored, in particular are fundamentally saved in the engine control unit, as is evident from FIG. 1.

(10) As is also clear from FIG. 1, a first actual load point LP.sub.Actual1, which is defined by the driver through a first target load point LP.sub.Target1, in particular through the accelerator pedal position, is present at time t.sub.0 or between times t.sub.0 and t.sub.1. The driver now calls for a load jump at time t.sub.1, namely a load increase, in particular actuates the vehicle's accelerator pedal, so that the second target load point LP.sub.Target2 is now applied in control terms in order to shift the actual load point LP.sub.Actual1 of the internal combustion engine in the direction of the second target load point LP.sub.Target2 or to implement the actual load jump.

(11) Shown in FIG. 1 are the actual load points LP.sub.Actual of the internal combustion engine or the curve of the actual engine loads after the corresponding target load point demand, which ramp up over the time t, here from the time t.sub.1 in the direction of the second target load point LP.sub.Target2 until the time t.sub.4, wherein the actual load jump is completed at time t.sub.4, namely the corresponding actual load point LP.sub.Actual/LP.sub.Actual2 then corresponds to the second target load point LP.sub.Target2.

(12) It can also be seen from FIG. 1 that, at least for the specific control period between the times t.sub.1 and t.sub.4, at least one regulating control limit curve GRS.sub.Curve (here a first and second regulating control limit curve GRS.sub.Curve) is determined and/or specific regulating control limit values GRS are defined (or can be calculated in the engine control unit), wherein, according to the method in accordance with the invention, a comparison of the relevant regulating control values RS with the relevant regulating control limit values GRS then takes place at specific relevant times t during the control period, and wherein the relevant lower control value is then used to drive the relative location of the intake camshaft. The abovementioned disadvantages are avoided or reduced by this means.

(13) To illustrate the results of the aforementioned comparison, a specific region between the times t.sub.1 and t.sub.4 is shown hatched in FIG. 1. At least in this region, the lower control value in each case is used for moving the intake camshaft, or the movement of the intake camshaft is then correspondingly limited, in particular to a maximum of this value in the “late” direction.

(14) As is now also clear from FIG. 1, within the control period here, in particular between the times t.sub.1 and t.sub.4 here, relevant specific stationary regulating control limit values GRS.sub.stationary are now associated with multiple relevant specific actual load points LP.sub.Actual or are defined correspondingly and/or a stationary regulating control limit curve GRS.sub.Curve_stationary is determined and/or defined for the control period, as is schematically represented by the curve of the line. In particular, corresponding regulating control limit values GRS.sub.stationary are saved for specific actual load points LP.sub.Actual of the internal combustion engine (in particular, are saved in characteristic maps and/or are correspondingly “populated with data”). These specific relevant stationary regulating control limit values GRS.sub.stationary, which are associated with specific relevant stationary actual load points LP.sub.Actual of the internal combustion engine, have been determined in advance, in particular on a test stand for stationary specific actual load conditions of the internal combustion engine. The specific stationary regulating control limit values GRS.sub.stationary are saved and/or stored in the engine control unit, in particular as a characteristic map and/or are stored in the engine control unit as a stationary regulating control limit curve GRS.sub.Curve_stationary.

(15) The regulating control limit curve GRS.sub.Curve_stationary that can be seen in FIG. 1 is a “first” regulating control limit curve GRS.sub.Curve here. These values/control values defined in this way could already be used for the abovementioned comparison and for carrying out the method according to the invention, with the relevant smaller value/control value then being used for driving the relative location of the intake camshaft. In the especially preferred embodiment of the method according to the invention, however, a relevant dynamic regulating control limit value GRS.sub.dynamic is used for the comparison mentioned above, in particular the “second” regulating control limit curve GRS.sub.Curve visible in FIG. 1, which corresponds to a dynamic regulating control limit curve GRS.sub.Curve_dynamic; this is described again in greater detail below in the explanation of the especially preferred embodiment of the invention.

(16) In particular, it is also possible that a multiplicity of such stationary regulating control limit curves for an extremely wide variety of load jumps, which is to say for an extremely wide variety of load increases, can be stored in the engine control unit, wherein the individual relevant actual load points of the internal combustion engine are then associated with the corresponding stationary regulating control limit values for specific load jumps. Fundamentally, however, relevant specific stationary regulating control limit values GRS.sub.stationary are associated, in particular, with at least the relevant specific actual load points of the internal combustion engine, in particular independently of desired load jumps.

(17) As FIG. 1 also shows, the combustion chamber heating T.sub.BRC is likewise represented over the time t by the corresponding line for the load jump represented here in FIG. 1 or the load increase represented here. The corresponding dash-dotted line T.sub.BRC in FIG. 1 is intended to schematically represent the combustion chamber heating for the load jump or for the load increase of the internal combustion engine shown here. This line T.sub.BRC, which in particular is determined virtually, results and/or is defined on the basis of characteristic delay times t.sub.BRC, wherein a characteristic delay time t.sub.BRC is represented by way of example here in FIG. 1 as a horizontal arrowed line between the curve LP.sub.Actual_curve and the line T.sub.BRC. In particular, a relevant characteristic delay time t.sub.BRc is associated with each actual load point LP.sub.Actual of the internal combustion engine, in particular is saved in a characteristic map and/or correspondingly “populated with data,” wherein this relevant characteristic delay time or the relevant value defined thereby corresponds to a delay time that the internal combustion engine requires from achievement of the relevant actual load point LP.sub.Actual until the internal combustion engine has then also achieved its new, stationary heating state. Or in other words: A relevant characteristic delay time t.sub.BRc, in particular determined on a test stand, is associated in particular with each different specific actual load point LP.sub.Actual of the internal combustion engine, with the aid of which delay time the (virtual) line shown here in FIG. 1 is produced for the combustion chamber heating T.sub.BRC. In particular, a corresponding, stationary new, in particular higher, temperature is present in the new, stationary heating state of the combustion chamber, which also merits mention here.

(18) With the aid of the relevant specific stationary regulating control limit values GRS.sub.stationary, dynamic regulating control limit values GRS.sub.dynamic, likewise represented by the line visible in FIG. 1 of the dynamic regulating control limit curve GRS.sub.Curve_dynamic shown here, are now determined and/or calculated as a function of the combustion chamber heating T.sub.BRC or of the relevant characteristic delay time t.sub.BRc (for the relevant “characteristic combustion chamber heating”). As is evident in FIG. 1, the corresponding dynamic regulating control limit curve GRS.sub.Curve_dynamic has a similar characteristic to the combustion chamber heating T.sub.BRC (except reflected at an x-axis having a parallel displacement). In other words, in order to determine/calculate the dynamic regulating control limit curve GRS.sub.Curve_dynamic or the relevant dynamic regulating control limit values GRS.sub.dynamic, the stationary regulating control limit curve GRS.sub.Curve_stationary is time delayed or is time delayed in control terms, in particular based on the relevant characteristic delay times t.sub.BRc.

(19) According to the exemplary embodiment of the method according to the invention, the relevant dynamic regulating control limit values GRS.sub.dynamic and/or the dynamic regulating control limit values GRS.sub.dynamic arising from the dynamic regulating control limit curve GRS.sub.Curve_dynamic are now used as the relevant regulating control limit values GRS for the comparison with the regulating control values RS.

(20) Consequently, in the especially preferred embodiment of the method according to the invention the “second” regulating control limit curve GRS.sub.Curve visible here in FIG. 1, which corresponds to the dynamic regulating control limit curve GRS.sub.Curve_dynamic, is used for the abovementioned comparison, which is to say the corresponding dynamic regulating control limit values GRS.sub.dynamic are used for the comparison with the regulating control values RS. The relevant lower value is then used for carrying out the method according to the invention in the especially preferred embodiment, namely for control/adjustment of the intake camshaft, in particular in order to limit the movement of the intake camshaft in the “late” direction to a maximum of this value/control value.

(21) In FIG. 1, the hatched region, which is intended here to clarify the selection or the selection region of the relevant smaller or lower control values, results from the illustration between the times t.sub.1 and t.sub.4. In other words, the “peak” of the regulating control value curve RS.sub.Curve projecting above the hatched region is “cut off,” or these regulating control values RS defined in this way are not taken into account in the method according to the invention. As FIG. 1 shows, only the corresponding regulating control values RS that are between the times t.sub.1 and t.sub.2 or t.sub.3 and t.sub.4, and which in particular are below the dynamic regulating control limit curve GRS.sub.dynamic, in other words only the specific regulating control values RS in the time periods t.sub.1 and t.sub.2 or t.sub.3 and t.sub.4, are then used for control in the method according to the invention. In particular, in the time period between the times t.sub.2 and t.sub.3, the dynamic regulating control limit values GRS.sub.dynamic are then used for the method according to the invention in the especially preferred embodiment. Quite fundamentally, it is also possible that in a different embodiment of the method according to the invention, the “first” curve GRS.sub.Curve of the stationary regulating control limit values GRS.sub.stationary also shown in FIG. 1 is then used “for example for the comparison of the regulating control values RS” with the relevant regulating control limit values GRS. This is also fundamentally possible, although in the especially preferred embodiment, as mentioned above, the dynamic regulating control limit curve GRS.sub.Curve_dynamic is used as the regulating control limit curve GRS.sub.Curve, in particular for the relevant comparison, since it is possible in this design to realize the greatest potential of the internal combustion engine, in particular without the risk of engine knocking.

(22) In particular, the method according to the invention is implemented in an internal combustion engine designed as an Otto engine, wherein the pressure in the intake system is at least partially achieved and/or controlled with the aid of an exhaust-gas turbocharger that is provided.

(23) In particular, the relevant characteristic map and/or the relevant dynamic regulating control limit curve GRS.sub.Curve_dynamic is then also determined and/or calculated, in particular based on a relevant stationary regulating control limit curve GRS.sub.Curve_stationary and based on a characteristic combustion chamber heating “T.sub.BRC” or on the characteristic delay times t.sub.BRc corresponding thereto, as explained above.

(24) Finally, FIG. 2 shows a schematic block diagram, in particular a schematic representation, of a section of the control and/or regulating system or of the execution of the method according to the invention with the control paths A, B or the sub-paths BA, BB.

(25) As is clear from FIG. 2, in this design a regulating control value RS is first routed to a comparing element 1, in particular through a first control path A. Through a second control path B (sub-path BA), an applicable specific stationary regulating control limit value GRS.sub.stationary is first routed to a circuit element 2 from saved/stored characteristic maps or stored stationary regulating control limit curves GRS.sub.Curve_stationary, on the one hand as a function of the relevant actual load point of the internal combustion engine and/or the actual speed of the internal combustion engine, wherein, again as a function of the relevant actual load point and/or the relevant actual speed of the internal combustion engine, a relevant characteristic delay time t.sub.BRc, which corresponds to a delay time until the internal combustion engine has achieved its new, stationary heating state for the relevant actual load point LP.sub.Actual, is routed to the same circuit element 2 in parallel through the control path/sub-path BB. The circuit element 2, designed as a time delay element, then calculates from the relevant stationary regulating control limit value GRS.sub.stationary, as a function of the relevant value of the relevant characteristic delay time t.sub.BRc, a thusly determined/calculated dynamic regulating control limit value GRS.sub.dynamic, which is routed to the comparing element 1. The so-called “selection of the minimum” then takes place here; the lower of the values routed to the comparing element 1 is selected or used for carrying out the method according to the invention, as already described above. The execution of this abovementioned regulation takes place in particular constantly or continuously during a load jump or a desired load increase.

(26) A control and/or regulating circuit is provided that has at least one first circuit element 1 designed as a comparing element and at least one second circuit element 2 designed as a time delay element. Firstly, the regulating control values RS that are fundamentally stored in the engine control unit by the engine control unit are routed to the first circuit element 1 through a first control path A. A second control path B is provided that has two sub-paths BA and BB, wherein a stationary regulating control limit value GRS is routed to the second circuit element 2 through a first sub-path BA and a value t.sub.BRc for a “characteristic delay time” is routed through the second sub-path BB. The second circuit element 2 determines a dynamic regulating control limit value GRS.sub.dynamic based on the value routed to the second circuit element 2.

(27) The selection of a minimum and/or a comparison takes place with the aid of the first circuit element 1, wherein the dynamic regulating control limit value GRS.sub.dynamic of the second circuit element 2 is routed to the first circuit element 1, wherein the relevant lower value or control value is used for driving the relative location of the intake camshaft.

(28) By way of example, when the value 0.95, in particular, is routed to the comparing element 1 as regulating control value RS between the times t.sub.2 and t.sub.3 and the value 0.85 is routed to it as dynamic regulating control limit value GRS.sub.dynamic, for example, the value 0.85 is then used here for moving the intake camshaft as the lower value for control/adjustment of the intake camshaft. Thus, the smaller value/control value is used so that the movement of the intake camshaft is limited to a lower value, which is to say a movement of the intake camshaft in the “late” direction is limited to a maximum of the lower value/control value.

(29) At this point it should be mentioned that it is possible to implement an absolute camshaft position, an offset from the position in stationary operation, or an interpolation factor between two defined camshaft limit locations, or a phase shift for the purpose of defining the permissible camshaft positioning travel or, in other words, for the movement of the intake camshaft. A corresponding value such as, in particular, between “0” and “1” for a movement of the intake camshaft from “early” to “late” (or vice versa) in the above example can then appropriately correspond to this example.

(30) A significant advantage of the method according to the invention over the methods known hitherto is essentially the continuous, in particular constant, adjustment of the intake camshaft positioning travel limits to the preceding actual load conditions of the internal combustion engine. Deactivation of intake camshaft movement is no longer necessary.

(31) In the method according to the invention, firstly, a maximum permissible positioning travel of the intake camshaft in the thermally settled state, in particular an applicable specific stationary regulating control limit value GRS.sub.stationary, is associated with each achievable actual load point as a parameter set. If the internal combustion engine is at a specific stationary actual load point, then the relevant defined and/or calculated regulating control value RS is applicable for the movement of the intake camshaft. In the event of a change to a more heavily thermally loaded operating point, which is to say in the case of a load increase of the internal combustion engine, a dynamic regulating control limit value GRS.sub.dynamic is determined. In order to determine the dynamic regulating control limit value GRS.sub.dynamic, a stationary regulating control limit value GRS.sub.stationary is tracked with the typical/characteristic time behavior (t.sub.BRc) for the heating of the combustion chamber, while a selection of the minimum from the regulating control values and the dynamic regulating control limit values then takes place for controlling the intake camshaft, in particular, and the lower value of these two control values is used as the control value to limit the movement of the intake camshaft in the “late” direction. A selection of a maximum takes place for the adjustment/control of the exhaust camshaft. This also merits being mentioned again at this point.

(32) As a result, the abovementioned disadvantages are avoided, and corresponding advantages are achieved.

(33) The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.