Method for determining the state of rotation of a camshaft of a vehicle engine

Patent metadata

Field	Value
Publication number	US-10634077-B2
Application number	US-201615745659-A
Country	US
Kind code	B2
Filing date	Jul 14, 2016
Priority date	Jul 21, 2015
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

Disclosed is a method for determining the state of rotation of a camshaft of a vehicle engine, notable in that the method for determining the state of rotation of the camshaft determines that the state of rotation of the camshaft is “in the process of stalling”, corresponding to an intermediate state of rotation, when the time elapsed since the last detection of a camshaft wheel tooth-front by the sensor exceeds Tcam_cal, Tcam_cal being defined as the theoretical length of time needed for the camshaft wheel to cover an angular distance equal to the maximum angular distance separating two successive camshaft wheel tooth-fronts at a camshaft rotational speed corresponding to a predetermined low engine speed higher than the minimum engine speed tolerated by the engine.

First claim

The invention claimed is:

1. A method for determining a state of rotation of a camshaft of a vehicle engine equipped with a crankshaft, detecting means of detecting whether a rotation of the crankshaft is stopped, a camshaft wheel that is coupled to the camshaft and comprises a plurality of teeth, and a sensor that faces the camshaft wheel and detects passage past said sensor of a tooth-front of any tooth of the plurality of teeth,
the method comprising:
on condition that
the engine has not been synchronized,
either i) the crankshaft is detected by the detecting means as being stopped or ii) the engine has not begun a synchronization process, and
the camshaft wheel is exhibiting a state of rotation of “rotating”,

determining said state of rotation of the camshaft as being one of:
“rotating”, as long as time elapsed since a last detection of a camshaft wheel tooth-front by the sensor has not reached a theoretical length of time (Tcam_cal) required for the camshaft wheel to cover an angular distance equal to a maximum angular distance separating two successive camshaft wheel tooth-fronts at a camshaft rotational speed corresponding to a predetermined low engine speed higher than the minimum engine speed tolerated by said engine,
“stopped”, when the time elapsed since the last detection of the camshaft wheel tooth-front by the sensor becomes greater than a theoretical length of time (Tcam) required for the camshaft wheel to cover an angular distance equal to the maximum angular distance separating two successive camshaft wheel tooth-fronts at a camshaft rotational speed corresponding to the minimum engine speed tolerated by said engine, or
“in the process of stalling”, when the time elapsed since the last detection of the camshaft wheel tooth-front by the sensor becomes greater than Tcam_cal while being less than Tcam, where Tcam_cal<Tcam,

wherein said method of determining the state of rotation of a camshaft also determines that the state of rotation of a camshaft is “stopped” when said method of determining the state of rotation of the camshaft has determined that the state of rotation of a camshaft is “in the process of stalling”.

2. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 1 , wherein Tcam_cal is approximately equal to 0.12 sec.

3. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 1 ,
wherein the engine is a vehicle combustion engine, and
wherein the predetermined low speed is approximately equal to 200 rpm.

4. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 3 , wherein Tcam_cal is approximately equal to 0.12 sec.

5. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 1 ,
wherein the engine is a vehicle combustion engine, and
wherein the minimum speed tolerated by the engine is approximately equal to 22 rpm.

6. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 5 , wherein Tcam_cal is approximately equal to 0.12 sec.

7. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 5 ,
wherein the engine is a vehicle combustion engine, and
wherein the predetermined low speed is approximately equal to 200 rpm.

8. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 7 , wherein Tcam_cal is approximately equal to 0.12 sec.

9. A method for determining a state of rotation of a camshaft of a vehicle engine equipped with a crankshaft, detecting means of detecting whether a rotation of the crankshaft is stopped, a camshaft wheel that is coupled to the camshaft and comprises a plurality of teeth, and a sensor that faces the camshaft wheel and detects passage past said sensor of a tooth-front of any tooth of the plurality of teeth,
the method comprising:
determining said state of rotation of the camshaft as being one of:
“rotating”, as long as time elapsed since a last detection of a camshaft wheel tooth-front by the sensor has not reached a theoretical length of time (Tcam_cal) required for the camshaft wheel to cover an angular distance equal to a maximum angular distance separating two successive camshaft wheel tooth-fronts at a camshaft rotational speed corresponding to a predetermined low engine speed higher than the minimum engine speed tolerated by said engine,
“stopped”, when the time elapsed since the last detection of the camshaft wheel tooth-front by the sensor becomes greater than a theoretical length of time (Tcam) required for the camshaft wheel to cover an angular distance equal to the maximum angular distance separating two successive camshaft wheel tooth-fronts at a camshaft rotational speed corresponding to the minimum engine speed tolerated by said engine, and
“in the process of stalling”, when the time elapsed since the last detection of the camshaft wheel tooth-front by the sensor becomes greater than Tcam_cal but is less than Tcam, where Tcam_cal<Tcam,
wherein, if the state of rotation is determined as “in the process of stalling”, and all the following conditions are met:
(A) the engine has not been synchronized,
(B) either i) the crankshaft is detected by the detecting means as being stopped or ii) the engine has not begun a synchronization process, and
(C) the camshaft wheel is initially exhibiting a state of rotation of “rotating”,

then the state of rotation is determined as “stopped”.

10. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 9 , wherein Tcam_cal is approximately equal to 0.12 sec.

11. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 9 ,
wherein the engine is a vehicle combustion engine, and
wherein the predetermined low speed is approximately equal to 200 rpm.

12. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 11 , wherein Tcam_cal is approximately equal to 0.12 sec.

13. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 9 ,
wherein the engine is a vehicle combustion engine, and
wherein the minimum speed tolerated by the engine is approximately equal to 22 rpm.

14. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 13 , wherein Tcam_cal is approximately equal to 0.12 sec.

15. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 13 ,
wherein the engine is a vehicle combustion engine, and
wherein the predetermined low speed is approximately equal to 200 rpm.

16. The method for determining the state of a camshaft of a vehicle engine as claimed in claim 15 , wherein Tcam_cal is approximately equal to 0.12 sec.

Assignees

• Continental Automotive France
• Continental Automotive Gmbh

Inventors

• Mazenc Christophe

Classifications

• F01L2800/03

  Stopping; Stalling · CPC title

• F01L2820/042

  Crankshafts position · CPC title

• F02D13/0219

  by shifting the phase, i.e. the opening periods of the valves are constant · CPC title

• F01L2820/041

  Camshafts position or phase sensors · CPC title

• F02D41/0097 Primary

  using means for generating speed signals · CPC title