Method to control an electromechanical linear actuator device for an internal combustion engine
A method is described to control an actuation profile of an electromechanical linear actuator device of an internal combustion engine designed to control the movement of a component; the internal combustion engine comprises a sensor, which faces the actuator device and is designed to detect the noise generated by the movement of the component; the method comprises the steps of acquiring, by means of the sensor, the intensity of a signal generated by the impact of the component against a limit stop; identifying a first listening window of the signal associated with said impact; calculating a noise index inside the listening window; comparing the noise index with a reference value; and controlling the actuation profile of the actuator device based on this comparison.
1. A method to control an actuation profile of an electromechanical linear actuator device ( 20 ) for an internal combustion engine (ICE); wherein the actuator device ( 20 ) is designed to control the movement of a movable armature ( 27 ) moving towards a first limit stop position defined by a fixed mechanical abutment ( 25 ) and vice versa; the internal combustion engine (ICE) comprises a sensor ( 31 ), which is arranged close to the actuator device ( 20 ) and is designed to detect the noise generated by the movement of the movable armature ( 27 ); the method comprises the steps of:
acquiring, by means of the sensor ( 31 ), the intensity of a signal (S) generated by the impact of the movable armature ( 27 ) against the fixed mechanical abutment ( 25 );
identifying a first listening window (OW) in the signal (S) detected by the sensor ( 31 ); wherein the first listening window (OW) identifies the impact of the movable armature ( 27 ) against the fixed mechanical abutment ( 25 );
calculating a first noise index (IDRC) of the signal (S) detected by the sensor ( 31 ) inside the first listening window (OW);
comparing the first noise index (IDRC) with at least one first reference value (I REF ); and
changing a time (T ON-MAIN ) needed to reach the maximum value of the current absorbed by the actuator device ( 20 ) based on the comparison between the first noise index (IDRC i ) and the first reference value (I REF ), namely
decreasing said time (T ON-MAIN ) needed to reach the maximum absorbed current value by a first value (Δt 2 ), in case the first noise index (IDRC) exceeds the respective first reference value (I REF ); or
increasing said time (T ON-MAIN ) needed to reach the maximum absorbed current value by a second value (Δt 3 ), in case the first noise index (IDRC) is smaller than or equal to the respective first reference value (I REF ); and
diagnosing a fault of the actuator device ( 20 ), in case said time (T ON-MAIN ) needed to reach the maximum absorbed current value exceeds a maximum value (T ON-MAINmax ).
2. The method according to claim 1 , wherein the actuator device ( 20 ) is designed to slow down the movement of a piston ( 14 ) moving towards a second limit stop position defined by a fixed closing disc ( 15 ); and the sensor ( 31 ) is suited to detect the noise generated by the movement of the piston ( 14 );
and comprising the further steps of:
acquiring, by means of the sensor ( 31 ), the intensity of a signal (S) generated by the impact of the piston ( 14 ) against the fixed closing disc ( 15 );
dividing the signal (S) detected by the sensor ( 31 ) into a plurality of listening windows (CW i );
calculating a second noise index (IDRC i ) of the signal (S) detected by the sensor ( 31 ) for each listening window (CW i );
comparing the maximum value (IDRC MAX ) of the second noise indexes (IDRC i ) with at least one second reference value (IDRR); and
changing the times of the actuation profile of the actuator device ( 20 ) based on the comparison between the maximum value (IDRC MAX ) and the second reference value (IDRR).
3. The method according to claim 2 and comprising the further step of:
identifying the listening window (CWi) containing the maximum value (IDRC MAX );
changing the times of the actuation profile of the actuator device ( 20 ) based on the position of the listening window (CW i ) having the maximum value (IDRC MAX ) in the actuation profile.
4. The method according to claim 3 and comprising the further step of changing a time (T OFF2 ) needed to reduce the speed of the piston ( 14 ) by a third value (Δt) based on the position of the listening window (CW i ) having the maximum value (IDRC MAX ) in the actuation profile.
5. The method according to claim 4 and comprising the further steps of:
increasing said time (T OFF2 ) needed to reduce the speed of the piston ( 14 ) by a quantity equal to the third value (Δt), in case the listening window (CW i ) having the maximum value (IDRC MAX ) in the actuation profile proceeds with a closing command; or
decreasing said time (T OFF2 ) needed to reduce the speed of the piston ( 14 ) by a quantity equal to the third value (Δt), in case the listening window (CW i ) having the maximum value (IDRC MAX ) in the actuation profile follows the closing command.
6. The method according to claim 1 , wherein the first noise index (IDRC) and the second noise index (IDRC i ) may be calculated using the following formula:
IDRC=MAXs( t ) t2 t1 −MINs( t ) t2 t1 , where
IDRC is the noise index in the respective listening window (OW; CW i );
s(t) is the signal detected by the sensor ( 31 ); and
t 1 , t 2 represents the time instants defining the respective listening window (OW; CW i ).
7. The method according to claim 1 , wherein the first noise index (IDRC) and the second noise index (IDRC i ) may be calculated using the following formula:
IDRC
=
1
N
∑
t
=
t
1
t
N
S
^
(
t
)
,
where
IDRC is the noise index in the respective listening window (OW; CW i );
Ŝ(t) is the signal detected by the sensor ( 31 ) and filtered in time; and
t 1 , t N represents the time instants defining the respective listening window (OW; CW i ).
8. The method according to claim 1 , wherein the first noise index (IDRC) and the second noise index (IDRC i ) may be calculated using the following formula:
IDRC
=
MAX
f
0
≤
f
≤
f
1
S
^
(
f
)
,
where
IDRC is the noise index in the respective listening window (OW; CW i );
Ŝ(f) is the signal detected by the sensor ( 31 ) and processed by operating a fast Fourier transform; and
f 0 , f i represents the ends of the band of frequencies analysed in the signal processed by operating a fast Fourier transform inside the respective listening window (OW; CW i ).
9. The method according to claim 1 , wherein the first noise index (IDRC) and the second noise index (IDRC i ) may be calculated using the following formula:
IDRC
=
1
N
∑
f
=
f
1
f
N
S
^
(
f
)
,
where
IDRC is the noise index in the respective listening window (OW; CW i );
Ŝ(f) is the signal processed by operating a fast Fourier transform; and
f 1 , f N represents the ends of the band of frequencies analysed in the signal processed by operating a fast Fourier transform inside the respective listening window (OW; CW i ).
10. The method according to claim 1 , wherein the sensor ( 31 ) is a microphone sensor ( 31 ) facing the actuator device ( 20 ).
11. The method according to claim 1 , wherein the sensor ( 31 ) is a vibration sensor ( 31 ) integrated in a body of the actuator device ( 20 ).
12. The method according to claim 1 , wherein the sensor ( 31 ) is a vibration sensor ( 31 ) arranged externally on the body of the actuator device ( 20 ).