Method for detecting physical stoppage of an engine
View Patent ↗Disclosed is a method for detecting physical stoppage of an internal combustion engine, including: at least four cylinders, a set of cylinder pressure sensors, configured such that, over the course of a combustion cycle of the engine, there is at least one cylinder in the compression or expansion phase whose pressure is measured by a pressure sensor of the set, the method including the following steps: measuring the pressure in a cylinder in the compression or expansion phase, calculating, from the pressure measured in the cylinder, a ratio between a pressure variation in the cylinder and the pressure in the cylinder, and detecting a physical stoppage of the engine if the measured pressure is decreasing and if the calculated ratio is constant.
1. A method for detecting physical stoppage of an internal combustion engine ( 1 ) comprising:
at least four cylinders ( 10 ),
a set ( 20 ) of cylinder-pressure sensors ( 21 ), which is configured so that throughout an engine combustion cycle, there is at least one cylinder ( 10 ) in the compression or expansion phase the pressure of which is measured by a pressure sensor ( 21 ) of the set ( 20 ),
the method comprising:
the pressure in a cylinder ( 10 ) in the compression or expansion phase is measured,
a ratio between a variation in pressure in the cylinder ( 10 ) and the pressure in the cylinder is calculated ( 400 ) from the pressure measured in the cylinder, and
a physical stoppage of the engine is detected ( 500 ) if the measured pressure is decreasing and if the calculated ratio is constant.
2. The detection method as claimed in claim 1 , wherein the step of measuring the pressure in a cylinder ( 10 ) comprises the acquisition ( 100 ) of pressure values at an acquisition frequency greater than or equal to 1 kHz, and the smoothing ( 200 ) of the acquired values.
3. The detection method as claimed in claim 1 , wherein the step ( 400 ) of calculating the ratio between a variation in pressure in the cylinder and the pressure in the cylinder involves calculating, over a period T, the quantity
Δ
P
(
T
N
+
1
)
P
(
T
N
+
1
)
=
[
P
(
T
N
)
-
P
(
T
N
+
1
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]
P
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T
N
+
1
)
and comparing said quantity with high and low values, so that if the values of said quantity are comprised between said high and low values then said quantity is considered to be constant.
4. The detection method as claimed in claim 3 , wherein a physical stoppage of the engine is detected when the quantity ΔP/P is comprised between the high and low values, and the pressure is decreasing over a determined duration.
5. The detection method as claimed in claim 4 , wherein the determined duration is comprised between 20 and 150 ms.
6. The detection method as claimed in claim 3 , comprising a preliminary step ( 90 ) of determining the high and low values, said preliminary step involving calculating the quantity ΔP/P for a plurality of identical stopped engines, and at a plurality of ambient temperatures.
7. A non-transitory computer-readable medium on which is stored a computer program, containing coded instructions for implementing the method as claimed in claim 1 , when implemented by a processing unit ( 30 ) comprising a computer ( 31 ) and a communications interface ( 33 ) for communicating with the pressure sensors ( 21 ).
8. A processing unit ( 30 ), comprising a computer ( 31 ) and a communications interface ( 33 ) for communicating with the pressure sensors ( 21 ), said computer being configured to implement the method as claimed in claim 1 .
9. An internal combustion engine ( 1 ) comprising:
at least four cylinders ( 10 ),
a set ( 20 ) of cylinder-pressure sensors ( 21 ), which is configured so that throughout an engine combustion cycle, there is at least one cylinder ( 10 ) in the compression or expansion phase the pressure of which is measured by a pressure sensor ( 21 ) of the set ( 20 ),
a processing unit ( 30 ), comprising a computer ( 31 ) and a communications interface ( 33 ) for communicating with the pressure sensors ( 21 ),
wherein the computer ( 31 ) is configured to implement the method as claimed in claim 1 .
10. The internal combustion engine ( 1 ) as claimed in claim 9 , wherein the set ( 20 ) of cylinder ( 10 ) pressure sensors ( 21 ) is configured so that throughout an engine ( 1 ) combustion cycle, there is at least one cylinder ( 10 ) the pressure of which, measured by a pressure sensor ( 21 ) of the set ( 20 ), is greater than at least 3 bar.
11. The internal combustion engine ( 1 ) as claimed in claim 10 , wherein the set of cylinder-pressure sensors comprises one cylinder-pressure sensor for each cylinder of the engine.
12. The detection method as claimed in claim 2 , wherein the step ( 400 ) of calculating the ratio between a variation in pressure in the cylinder and the pressure in the cylinder involves calculating, over a period T, the quantity
Δ
P
(
T
N
+
1
)
P
(
T
N
+
1
)
=
[
P
(
T
N
)
-
P
(
T
N
+
1
)
]
P
(
T
N
+
1
)
and comparing said quantity with high and low values, so that if the values of said quantity are comprised between said high and low values then said quantity is considered to be constant.
13. The detection method as claimed in claim 4 , comprising a preliminary step ( 90 ) of determining the high and low values, said preliminary step involving calculating the quantity ΔP/P for a plurality of identical stopped engines, and at a plurality of ambient temperatures.
14. The detection method as claimed in claim 5 , comprising a preliminary step ( 90 ) of determining the high and low values, said preliminary step involving calculating the quantity ΔP/P for a plurality of identical stopped engines, and at a plurality of ambient temperatures.
15. A non-transitory computer-readable medium on which is stored a computer program, containing coded instructions for implementing the method as claimed in claim 2 , when implemented by a processing unit ( 30 ) comprising a computer ( 31 ) and a communications interface ( 33 ) for communicating with the pressure sensors ( 21 ).
16. A non-transitory computer-readable medium on which is stored a computer program, containing coded instructions for implementing the method as claimed in claim 3 , when implemented by a processing unit ( 30 ) comprising a computer ( 31 ) and a communications interface ( 33 ) for communicating with the pressure sensors ( 21 ).
17. A non-transitory computer-readable medium on which is stored a computer program, containing coded instructions for implementing the method as claimed in claim 4 , when implemented by a processing unit ( 30 ) comprising a computer ( 31 ) and a communications interface ( 33 ) for communicating with the pressure sensors ( 21 ).
18. A non-transitory computer-readable medium on which is stored a computer program, containing coded instructions for implementing the method as claimed in claim 5 , when implemented by a processing unit ( 30 ) comprising a computer ( 31 ) and a communications interface ( 33 ) for communicating with the pressure sensors ( 21 ).
19. A non-transitory computer-readable medium on which is stored a computer program, containing coded instructions for implementing the method as claimed in claim 6 , when implemented by a processing unit ( 30 ) comprising a computer ( 31 ) and a communications interface ( 33 ) for communicating with the pressure sensors ( 21 ).
20. A processing unit ( 30 ), comprising a computer ( 31 ) and a communications interface ( 33 ) for communicating with the pressure sensors ( 21 ), said computer being configured to implement the method as claimed in claim 2 .