Engine order and road noise control
Exemplary engine order and road noise control systems and methods include directly picking up road noise from a structural element of a vehicle to generate a first sense signal representative of the road noise, detecting harmonics of an engine of the vehicle to generate a second sense signal representative of the engine harmonics, and combining the first sense signal and the second sense signal to provide a combination signal representing the combination of the first sense signal and the second sense signal. The systems and methods further include broadband active noise control filtering to generate a filtered combination signal, and converting the filtered combination signal from the active noise control filtering into anti-noise and radiating the anti-noise to a listening position in an interior of the vehicle. The filtered combination signal is configured so that the anti-noise reduces the road noise and engine sound at the listening position.
1. An engine order and road noise control system comprising:
a first sensor configured to directly pick up road noise from a structural element of a vehicle, and to generate a first sense signal representative of the road noise;
a repetitions-per-minute (RPM) sensor configured to output a square wave signal with a single frequency corresponding to the RPM of an engine of the vehicle;
a low-pass filter configured to filter the first sense signal and to generate a first filtered sense signal;
a high-pass filter configured to directly filter the square wave signal to generate a second filtered sense signal;
an adder configured to sum the first filtered sense signal and the second filtered sense signal to provide a sum signal representing the sum of the first filtered sense signal and the second filtered sense signal;
a broadband active noise control filter configured to generate a filtered sum signal from the sum signal; and
a loudspeaker configured to convert the filtered sum signal provided by the broadband active noise control filter into anti-noise and to radiate the anti-noise to a listening position in an interior of the vehicle; wherein
the filtered first signal and the filtered second signal are configured so that the anti-noise reduces the road noise and engine sound at the listening position.
2. The system of claim 1 , wherein the broadband active noise control filter comprises:
a controllable filter electrically connected to the adder; and
a filter controller configured to receive the sum signal and to control the controllable filter according to the sum signal.
3. The system of claim 2 , further comprising a microphone disposed in the interior of the vehicle close at or adjacent to the listening position, wherein the microphone is configured to provide a microphone signal and the filter controller is configured to further control the controllable filter according to the microphone signal.
4. The system of claim 2 , wherein the filter controller is configured to control the controllable filter according to a least mean square algorithm.
5. The system of claim 1 , wherein the first sensor is an acceleration sensor attached to the structural element of the vehicle.
6. The system of claim 1 , wherein the RPM sensor is electrically or mechanically connected to the engine of the vehicle.
7. The system of claim 1 , wherein the second sensor is combined with an acoustic sensor disposed at or adjacent to the engine of the vehicle.
8. An engine order and road noise control method comprising:
directly picking up road noise from a structural element of a vehicle to generate a first sense signal representative of the road noise;
generating a square wave signal with a single frequency corresponding to a repetitions-per-minute (RPM) of an engine of the vehicle;
low-pass filtering of the first sense signal to generate a first filtered sense signal;
high-pass filtering to directly filter the square wave signal to generate a second filtered sense signal;
summing the first filtered sense signal and the second filtered sense signal to provide a sum signal representing the sum of the first filtered sense signal and the second filtered sense signal;
broadband active noise control filtering to generate a filtered sum signal from the sum; and
converting the filtered sum signal provided by the broadband active noise control filtering into anti-noise and radiating the anti-noise to a listening position in an interior of the vehicle; wherein
the filtered sum signal is configured so that the anti-noise reduces the road noise and engine sound at the listening position.
9. The method of claim 8 , wherein the broadband active noise control filtering comprises controlled filtering of the sum signal to provide the filtered sum signal to be converted into anti-noise, wherein the filtering is controlled according to the sum signal.
10. The method of claim 9 , further comprising picking up sound in the interior of the vehicle close at or adjacent to the listening position to provide a microphone signal, wherein the filtering is further controlled according to the microphone signal.
11. The method of claim 9 , wherein the filtering is controlled according to a least mean square algorithm.
12. The method of claim 8 , wherein the road noise is picked up from the structural element of the vehicle with an acceleration sensor attached to the structural element of the vehicle.
13. The method of claim 8 , wherein the square wave signal is provided by a RPM sensor mechanically or electrically connected to the engine of the vehicle and/or engine noise is provided by an acoustic sensor acoustically connected to the engine of the vehicle.
14. An engine order and road noise control system comprising:
a first sensor configured to receive road noise from a structural element of a vehicle, and to generate a first sense signal representative of the road noise;
a repetitions-per-minute (RPM) sensor configured to output a square wave signal with a single frequency corresponding to the RPM of an engine of the vehicle;
a low-pass filter configured to filter the first sense signal and to generate a first filtered sense signal;
a high-pass filter configured to directly filter the square wave signal to generate a second filtered sense signal;
an adder configured to sum the first filtered sense signal and the second filtered sense signal to provide a sum signal representing the sum of the first filtered sense signal and the second filtered sense signal;
a broadband active noise control filter configured to generate a filtered sum signal from the sum signal; and
a loudspeaker configured to convert the filtered sum signal into anti-noise and to radiate the anti-noise to a listening position within the vehicle; wherein
the filtered sum signal is configured so that the anti-noise reduces the road noise and engine sound.
15. The system of claim 14 , wherein the broadband active noise control filter comprises:
a controllable filter electrically connected to the adder and upstream of the loudspeaker; and
a filter controller configured to receive the sum signal and to control the controllable filter according to the filtered first signal and the filtered second signal.
16. The system of claim 15 , further comprising a microphone disposed in an interior of the vehicle close at or adjacent to the listening position, wherein the microphone is configured to provide a microphone signal and the filter controller is configured to further control the controllable filter according to the microphone signal.
17. The system of claim 15 , wherein the filter controller is configured to control the controllable filter according to a least mean square algorithm.