CONTROLLING AN INTERNAL COMBUSTION ENGINE WITH ADJUSTABLE CAMSHAFT

Abstract

A method is disclosed for controlling an internal combustion engine having a first adjustable camshaft for the actuating of first valve elements of the internal combustion engine. An effect of an actuation at least of a first valve element by the first camshaft on this valve element is detected. An actual position of the first camshaft and/or of a crankshaft driving the latter is detected on the basis of this detecting of the effect. An adjustment of the first camshaft is calibrated on the basis of a first deviation between this detected actual position and a predetermined required position.

Claims

1-15. (canceled)

16. A method for controlling an internal combustion engine having an adjustable camshaft for the actuating of a valve element of the internal combustion engine, the method comprising: detecting a first effect of an actuation of the first valve element by the first camshaft; detecting an actual position of at least one of the first camshaft and a crankshaft driving the first camshaft on the basis of the first detected effect; and calibrating an adjustment of the first camshaft on the basis of a first deviation between the detected actual position and a predetermined required position.

17. The method according to claim 16 further comprising: detecting a second effect of an actuation of a second valve element of the internal combustion engine by the first camshaft of the internal combustion engine; detecting an actual position of at least one of the first camshaft and the crankshaft driving the first camshaft on the basis of the second detected effect; and calibrating an adjustment of the first camshaft on the basis of a second deviation between the detected actual position and a predetermined required position.

18. The method according to claim 17, further comprising: detecting a third effect of an actuation of a third valve element of the internal combustion engine by a second camshaft of the internal combustion engine; detecting an actual position of at least one of the second camshaft and the crankshaft driving the second camshaft on the basis of the second detected effect; and calibrating an adjustment of the second camshaft on the basis of a second deviation between the detected actual position and a predetermined required position.

19. The method according to claim 17, wherein the adjustment of the first camshaft is calibrated on the basis of a mean value of the first and second deviations.

20. The method according to claim 16, further comprising: detecting a second effect of an actuation of a second valve element of the internal combustion engine by a second camshaft of the internal combustion engine; detecting an actual position of at least one of the second camshaft and the crankshaft driving the second camshaft on the basis of the second detected effect; and calibrating an adjustment of the second camshaft on the basis of a second deviation between the detected actual position and a predetermined required position.

21. The method according to claim 20, wherein the adjustment of the first and second camshafts is calibrated on the basis of a mean value of the first and second deviations.

22. The method according to claim 16, wherein detecting the first effect comprises detecting one of a start of an opening process, an end of the opening process, a start of a closing process or an end of the closing process for the first valve element.

23. The method according to claim 16, wherein the first detected effect is selecting from the group consisting of a force acting on the first valve element, a coupling arrangement between the first valve element and the first camshaft, an adjustment travel of the first valve element.

24. The method according to claim 16, where detecting the first effect comprises one of electrically detecting, capacitively detecting, piezoelectrically detecting or electromagnetically detecting the first effect.

25. The method according to claim 16, further comprising detecting the first effect with a predetermined reference adjustment of the camshaft.

26. The method according to claim 16, wherein a position of a camshaft comprises a position of the camshaft relative to a position of a crankshaft of the internal combustion engine.

27. The method according to claim 26, wherein calibrating an adjustment of a camshaft comprises modifying a predetermined camshaft required position.

28. The method according to claim 27, wherein the predetermined camshaft required position comprising a camshaft adjustment characteristic map.

29. The method according to claim 27, further comprising altering the camshaft required positions by at least 1° and not more than 10° crankshaft angle.

30. The method according to claim 26, wherein calibrating an adjustment of a camshaft comprises calibrating a camshaft adjustment device.

31. The method according to claim 30, further comprising altering the camshaft adjustment device by at least 1° and not more than 10° crankshaft angle.

32. The method according to claim 16, wherein the method is carried out during a start phase and at one predetermined operating point of the internal combustion engine.

33. A non-transitory computer readable medium comprising a program code having computer instructions, which when executed on a computer, is configured to carry out the method according to claim 16.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements.

[0053] FIG. 1 shows a portion of an internal combustion engine of a motor vehicle and a control for controlling the internal combustion engine according to an embodiment of the present; and

[0054] FIG. 2 is a flowchart for controlling the internal combustion engine according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0055] The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description.

[0056] FIG. 1 shows a portion of an internal combustion engine of a motor vehicle and a control for controlling the internal combustion engine according to an embodiment of the present disclosure. The internal combustion engine has a first valve element 10, which is able to be actuated by a first camshaft 20 in a manner known per se via a coupling arrangement with a roller cam follower 11 and with a hydraulic valve element clearance compensation 12. The internal combustion engine has further first valve elements which are able to be actuated in an identical manner via in each case a coupling arrangement with a roller cam follower and with a hydraulic valve element clearance compensation likewise by the first camshaft 20, and second valve elements, which are able to be actuated by a second camshaft 20′ in an identical manner, known per se, via in each case a coupling arrangement with a roller cam follower and with a hydraulic valve element clearance compensation. For more compact illustration, in FIG. 1 by way of example only one additional valve element 10′ is shown with roller cam follower 11′ and hydraulic valve element clearance compensation 12′, which likewise can be such a further first valve element able to be actuated by the first camshaft 20 or such a second valve element able to be actuated by the second camshaft 20′.

[0057] The internal combustion engine has in addition a crankshaft 30, which in a manner known per se is coupled via a camshaft adjustment device 31 in a variable manner with the first camshaft 20 and a camshaft adjustment device 31′ (which in FIG. 1 is illustrated in dashed lines, owing to the shared illustration of a further first and a second valve element 10′) with the second camshaft 20′, as indicated in FIG. 1 by a double-dot dashed coupling line.

[0058] The control includes an electronic control unit or ECU 40, which is signal-related to a sensor S1, for example a trigger wheel, for detecting a rotation angle of the first camshaft 20, a sensor S1′, for example a trigger wheel, for detecting a rotation angle of the second camshaft 20′ (which is illustrated in dashed lines in FIG. 1, owing to the shared illustration of a further first and a second valve element 10′), a (crankshaft) sensor S2 for detecting a position of the crankshaft 30 and optionally with sensors S3, S3′ for detecting an adjustment travel of the first and further first or respectively second valve element 10, 10′, or sensors S4, S4′ for detecting a force, which detect forces which act on the valve element clearance compensations 12, 12′. By the sensors S1, S1′ and S2, the ECU 40 detects an actual position or respectively actual phase shift of the first and second camshaft 20, 20′ relative to the crankshaft 30.

[0059] The ECU 40 controls the camshaft adjustment devices 31, 31′ or respectively an adjustment of the camshafts 20, 20′ and carries out, for this, a method, explained below with reference to FIG. 2, according to an embodiment of the present disclosure.

[0060] At S10, the ECU 40 checks whether a start phase of the internal combustion engine is present or respectively whether the internal combustion engine has just been started. If this is not the case (S10: “N”), it waits for a next start phase of the internal combustion engine.

[0061] When a start phase of the internal combustion engine is present (S10: “Y”), at S20 the ECU 40 adjusts the camshafts 20, 20′ into a reference adjustment, for example a zero- or respectively locking adjustment, in a further development it locks the camshaft adjustment device 30 during the following calibration in this position.

[0062] At S30, the ECU 40 checks whether the sensor S3 has detected a start of an opening process of the valve element 10. In a modification, the ECU 40 can also check in step S30 whether the sensor S3 has detected an end of a closing process of the valve element 10. Likewise, at S30 the ECU 40 can also check whether the sensor S4, on the basis of corresponding force values detected by the sensor S4, has detected a start of an opening process or an end of a closing process of the valve element 10.

[0063] As long as this is not the case (S30: “N”), the ECU 40 waits for such a detecting of an effect of an actuation of the valve element 10 by the camshaft 20 on the valve element 10.

[0064] With such a detection (S30: “Y”) the ECU 40 detects at S40 by the sensors S1, S2 an actual position, present here, of the first camshaft 20, compares this with a predetermined required position of the first camshaft 20 for or respectively during the opening or respectively closing of the valve element 10 and determines a deviation α.sub.1 between actual and required position. If, for example (for the configuration of a camshaft adjustment characteristic map or of the camshaft adjustment device 31) an opening or respectively closing is provided at a particular camshaft required position α.sub.N, d and if the ECU 40 detects this opening or respectively closing instead at a camshaft actual position α.sub.N, i, then it determines at S40 as a difference Δ.sub.1=α.sub.N, d−α.sub.N, i. If the difference Δ.sub.1 is therefore for example greater than zero, the valve element opens or respectively closes too early or respectively at an earlier position of the crankshaft 30.

[0065] At S50, the ECU 40 checks in an analogous manner whether the sensor S3 has detected a start of a further opening process of the valve element 10. In a modification, the ECU 40 can also check again at S50 whether the sensor S3 has detected an end of a further closing process of the valve element 10. Likewise, the ECU 40 can also check at S50 whether the sensor S4, on the basis of corresponding force values detected by the sensor S4, has detected a start of a further opening process or an end of a further closing process of the valve element 10.

[0066] Likewise, at S50 the ECU can also check whether the sensor S3′ has detected a start of an opening process of the further first valve element 10′. In a modification, the ECU 40 can again also check at S50 whether the sensor S3′ has detected an end of a closing process of the further first valve element 10′. Likewise, at S50 the ECU can also check whether the sensor S4′, on the basis of corresponding force values detected by the sensor S4′, has detected a start of an opening process or an end of a closing process of the further first valve element 10′.

[0067] As long as this is not the case (S50: “N”), the ECU 40 waits for such a detection.

[0068] With such a detection (S50: “Y”), the ECU 40 detects in at S60 in an analogous manner by the sensors S1, S2 an actual position, present there, of the first camshaft 20, compares this with a predetermined required position of the first camshaft 20 on opening or respectively closing of the valve element 10 or respectively 10′ and determines a second deviation Δ.sub.2 between this actual position and required position.

[0069] At S70, the ECU 40 averages the deviation Δ.sub.1, which was determined at S40 on detecting the opening or respectively closing of the first valve element 10, and the deviation Δ.sub.2, which was determined in step S60 on detecting the further opening or respectively closing of the first valve element 10 or respectively on detecting the opening or respectively closing of the further first valve element 10′, to an averaged deviation Δ=(Δ.sub.1+Δ.sub.2)/2.

[0070] Then at S70 it calibrates the adjustment of the first camshaft 20 on the basis of this averaged difference Δ. For this, in an embodiment, the ECU 40 shifts a camshaft adjustment characteristic map by the determined deviation Δ, by shifting every camshaft required position of this characteristic map by this difference Δ.

[0071] If, for example, it is established at S30-S70 that the camshaft 20 on an opening or respectively closing of the valves on average has, instead of a predetermined required position α.sub.N, d, an effective actual position α.sub.N, i, after S70, required values shifted accordingly by this offset A=α.sub.N, d−α.sub.N, i are provided for the camshaft adjustment device 31, so that it in fact realizes the actually desired actual value or respectively opening or respectively closing times.

[0072] The calibration of the adjustment of the camshaft 20 can be realized in particular by a corresponding shifting of a reference, in particular zero point or respectively benchmark of the camshaft adjustment characteristic map.

[0073] In another embodiment, at S70 for the calibration of the adjustment of the camshaft 20, the ECU 40 adjusts the camshaft adjustment device 31 or respectively a zero position of the camshaft adjustment device 31 by this offset A. When the camshaft adjustment device 31 then receives corresponding (adjustment) actuating instructions for the adjusting of the camshaft 20 (with respect to this zero position), it now adjusts control times of the valve elements 10, 10′ in the intended or respectively designated manner.

[0074] For the second camshaft 20′, the ECU 40 carries out in a parallel manner an analogous method, explained above with reference to FIG. 2.

[0075] While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.