Method for synchronizing an internal combustion engine

Patent metadata

Field	Value
Publication number	US-11466632-B2
Application number	US-201917293329-A
Country	US
Kind code	B2
Filing date	Nov 13, 2019
Priority date	Nov 14, 2018
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

The aim of the present invention is a method for synchronizing an engine comprising at least one movable piston of a four-stroke internal combustion engine, said method comprising a first step (e1) involving initializing a second memory space, a second step (e2) involving waiting for an edge on a fourth signal (CAM_TOT), a fourth step (e4) involving testing the value of a counter (CPT), an eighth step (e8) involving selecting the theoretical angular positions of the slots of the second signal (CAM_IN) relative to the edges of a first signal (CRK) and of the slots of a third signal (CAM_EX) relative to the edges of the first signal (CRK).

First claim

The invention claimed is:

1. A method for detecting the position of at least one movable piston in a cylinder of a four-stroke internal combustion engine, with the movement of the piston driving a crankshaft cooperating with at least one first camshaft and one second camshaft, the crankshaft also cooperating with a first target having a determined number of teeth on a first target periphery, the first camshaft cooperating with a second target and the second camshaft cooperating with a third target, the second target having a determined number of teeth on a second target periphery and the third target having a determined number of teeth on the third target periphery, a first sensor adapted, on the one hand, for detecting the passage of the teeth of the first target and, on the other hand, for generating a first signal (CRK), a second sensor adapted, on the one hand, for detecting the passage of the teeth of the second target and, on the other hand, for generating a second signal (CAM_IN), a third sensor adapted, on the one hand, for detecting the passage of the teeth of the third target and, on the other hand, for generating a third signal (CAM_EX), the second sensor and the third sensor being sensors of the current source type coupled in parallel, the parallel coupling enabling the generation of a fourth signal (CAM_TOT), the second sensor and the third sensor also being coupled to a computer responsible for engine management, the first signal (CRK) being made up of a determined number of edges corresponding to the number of teeth of the first target, the second signal (CAM_IN) being made up of slots corresponding to the passages of the teeth of the second target, the third signal (CAM_EX) being made up of slots corresponding to the passages of the teeth of the third target, the fourth signal (CAM_TOT) being made up of slots corresponding to a sum of the second signal (CAM_IN) and of the third signal (CAM_EX), a slot being made up of a rising edge and a falling edge, a first memory space adapted for storing theoretical angular positions of the slots of the second signal (CAM_IN) relative to the edges of the first signal (CRK) and of the slots of the third signal (CAM_EX) relative to the edges of the first signal (CRK), as well as the directions of the edges of said slots, said method being characterized in that it comprises:
a first step (e 1 ) involving initializing a second memory space adapted for storing information associated with the positions of the slots of the fourth signal (CAM_TOT) relative to the edges of the first signal (CRK), the first step (e 1 ) further comprising a step of initializing a counter (CPT) adapted for counting a number of revolutions completed by the first target;
a second step (e 2 ) involving waiting for an edge on the fourth signal (CAM_TOT), representing the passage of a tooth of the second target in front of the second sensor or the passage of a tooth of the third target in front of the third sensor, the second step (e 2 ) further comprising proceeding to a third step (e 3 ) when an edge is detected on the fourth signal (CAM_TOT);
the third step (e 3 ) involving recording, in the second memory space, on the one hand, the nature of the detected edge, i.e. either a rising edge or a falling edge, and, on the other hand, the angular position of said detected edge relative to the first target;
a fourth step (e 4 ) involving testing the value of the counter (CPT), in the case whereby the value of the counter (CPT) is equal to a value N then the method proceeds to a fifth step (e 5 ), otherwise it proceeds to the second step (e 2 );
the fifth step (e 5 ) involving waiting for a new edge on the fourth signal (CAM_TOT), and proceeding to a sixth step (e 6 ) when an edge is detected on the fourth signal (CAM_TOT);
the sixth step (e 6 ) involving computing an average of the angular position of the last detected edge with the value of the corresponding edge of the preceding revolution of the first target stored in the second memory space;
a seventh step (e 7 ) involving computing a range of angular positions α determined around the average value of the angular position of said detected edge;
an eighth step (e 8 ) involving selecting theoretical angular positions of the slots of the second signal (CAM_IN) relative to the edges of the first signal (CRK) and of the slots of the third signal (CAM_EX) relative to the edges of the first signal (CRK) when they are within the range of angular positions computed in the seventh step (e 7 ); in the case whereby no theoretical angular position of the slots of the second signal (CAM_IN) and of the third signal (CAM_EX) is within the range of the computed angular positions, then the method proceeds to a ninth step (e 9 ), in the case whereby a theoretical angular position of a slot of only one of the two signals (CAM_IN) or (CAM_EX) is within the range of computed angular positions, then the method proceeds to a tenth step (e 10 ), in the case whereby a single theoretical angular position of a single slot of the second signal (CAM_IN) and a single theoretical angular position of a single slot of the third signal (CAM_EX) are within the range of the computed angular positions, then the method proceeds to an eleventh step (e 11 );
the ninth step (e 9 ) involving generating a warning synonymous with a failure on at least one of the three signals;
the tenth step (e 10 ) involving not assigning the detected edge to the signal (CAM_IN or CAM_EX), with the non-assigning being for the signal (CAM_IN or CAM_EX) that does not have a slot, the theoretical angular position of which is within the range of computed angular positions of said edge;
the eleventh step (e 11 ) involving proceeding to the third step (e 3 ) in the case whereby the value of the counter (CPT) is less than the value N, otherwise the method proceeds to a twelfth step (e 12 ).

2. The synchronization method as claimed in claim 1 , characterized in that, during the eighth step (e 8 ), in addition, in the case whereby a theoretical angular position of a slot of only one of the two signals (CAM_IN) or (CAM_EX) is within the range of determined angular positions, the direction of said detected edge is compared with the direction of the corresponding signal (CAM_IN) or (CAM_EX).

3. The synchronization method as claimed in claim 1 , characterized in that, during the eighth step (e 8 ), in addition, in the case whereby a theoretical angular position of a slot of the second signal (CAM_IN) and a single theoretical angular position of a single slot of the third signal (CAM_EX) are within the range of determined angular positions, the direction of said detected edge is compared with the direction of the corresponding signal (CAM_IN) or (CAM_EX).

4. The synchronization method as claimed in claim 1 , characterized in that the value N of the counter (CPT) equals 2.

5. The synchronization method as claimed in claim 1 , characterized in that, in the sixth step (e 6 ), the average of the angular position of the detected edge is computed on N revolutions of the first target.

6. The synchronization method as claimed in claim 1 , characterized in that, in the case whereby at least one theoretical angular position of a single slot of the second signal (CAM_IN) and a single theoretical angular position of a single slot of the third signal (CAM_EX) are within the range of computed angular positions and when the counter (CPT) has reached a value N′, a twelfth step (e 12 ) is carried out involving applying a phase-shift of value (V) to one of the two targets.

7. The synchronization method as claimed in claim 6 , characterized in that, during a thirteenth step (e 13 ), the edges of the fourth signal (CAM_TOT) are detected and stored.

8. The synchronization method as claimed in

Assignees

• Vitesco Tech Gmbh

Inventors

• Rocher Jacques
• Leroy Yannick
• Marconato Benjamin

Classifications

• F02D41/222

  relating to the failure of sensors or parameter detection devices · CPC title

• F02B75/02

  Engines characterised by their cycles, e.g. six-stroke · CPC title

• F02D2041/001

  for engines with variable valve actuation · CPC title

• F02D41/009 Primary

  using means for generating position or synchronisation signals · CPC title

• F02P7/077

  Circuits therefor, e.g. pulse generators · CPC title