Method for identifying the edges on a camshaft target

Patent metadata

Field	Value
Publication number	US-9702786-B2
Application number	US-201314404651-A
Country	US
Kind code	B2
Filing date	Jun 4, 2013
Priority date	Jun 12, 2012
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

Process for identifying edges on a camshaft target ( 30 ) having a plurality of teeth on the periphery thereof, the plurality of teeth forming a series of M edges when the camshaft rotates through one revolution, the process including the following steps:
calculating, for each of the M edges, the characteristic:

CP
⁡

(
j
)

=

[

∑

i
=
1

N

⁢

⁢

P
⁡

(

j
-
i
+
1

)

+

∑

i
=

3
⁢

⁢
N

4
⁢

⁢
N

-
1

⁢

⁢

P
⁡

(

j
-
i

)

∑

i
=
N

3
⁢

⁢
N

-
1

⁢

⁢

P
⁡

(

j
-
i

)

]

N
≥
1

P(i) denoting the angular distance between the edge i and the preceding edge,
during the movement of the camshaft target, calculating, during an edge detection, an index:

CT
⁡

(
k
)

=

[

∑

i
=
1

N

⁢

⁢

T
⁡

(

k
-
i
+
1

)

+

∑

i
=

3
⁢

⁢
N

4
⁢

⁢
N

-
1

⁢

⁢

T
⁡

(

k
-
i

)

∑

i
=
N

3
⁢

⁢
N

-
1

⁢

⁢

T
⁡

(

k
-
i

)

]

N
≥
1

T(i) denoting the time elapsed since the appearance of the edge i−1 to the edge i,
comparing the index CT(k) with each of the CP(j), determining the position of the camshaft.

First claim

The invention claimed is:

1. A process for identifying edges on a camshaft target of an internal combustion engine rotating in a normal direction of rotation and controlled by a control unit, said camshaft target having a plurality of teeth on the periphery thereof, the plurality of teeth forming, for a position sensor facing said teeth, a series of significant edges when the camshaft rotates through one revolution, the significant edges being edges that are processed by identification logic, the process comprising the following steps:
a) calculating, for each of the significant edges, a characteristic relating to a position of the significant edges preceding said significant edge in accordance with the normal direction of rotation, said characteristic being defined by formula

CP
⁡

(
j
)

=

[

∑

i
=
1

N

⁢

⁢

P
⁡

(

j
-
i
+
1

)

+

∑

i
=

3
⁢

⁢
N

4
⁢

⁢
N

-
1

⁢

⁢

P
⁡

(

j
-
i

)

∑

i
=
N

3
⁢

⁢
N

-
1

⁢

⁢

P
⁡

(

j
-
i

)

]

N
≥
1

P(i) denoting the angular distance between the significant edge i and the preceding significant edge on the camshaft,
and storing at least these values CP(j), j ranging from 1 to the number of the significant edges, in a memory of the control unit,

b) defining a sub-list of significant edges and initializing the sub-list with all significant edges,
c) during the movement of the camshaft target, calculating, during a significant edge detection, an index relating to time intervals elapsed since the preceding significant edges, by the formula:

CT
⁡

(
k
)

=

[

∑

i
=
1

N

⁢

⁢

T
⁡

(

k
-
i
+
1

)

+

∑

i
=

3
⁢

⁢
N

4
⁢

⁢
N

-
1

⁢

⁢

T

Assignees

• Continental Automotive France
• Continental Automotive Gmbh

Inventors

• Zouboff Pierre
• Lachaize Jerome

Classifications

• G01M15/06 Primary

  by monitoring positions of pistons or cranks · CPC title

• F02P7/067

  Electromagnetic pick-up devices {, e.g. providing induced current in a coil} · CPC title

• F02D41/009 Primary

  using means for generating position or synchronisation signals · CPC title

• G01M15/046

  by monitoring revolutions (for detecting misfire G01M15/11) · CPC title

• F02D41/222

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