Active noise control for vehicles

Abstract

Aspects of the present invention relate to an active noise system (4), a vehicle (1) with an active noise system (4), a method for controlling an active noise system (4), a computer program for controlling an active noise system (4) and an active noise controller (40). The wading detection system (3) includes sensors (30, 31, 32, 33) for detecting a wading depth and a wading detection controller (34). The active noise system (4) includes speakers (41, 42) for modifying the exhaust noise emitted from the vehicle (1). The wading detection controller (34) is operable to detect or anticipate a predetermined wading depth (W.sub.1, W.sub.2) at which the speakers (41, 42) will come into contact with the water. The active noise controller (40) is configured to deactivate the speakers (41, 42) when the predetermined wading depth (W.sub.1, W.sub.2) is detected or anticipated by the wading detection controller (34).

Claims

1. An active noise system for external use on a vehicle, the system comprising: audible output means mounted to an underside of the vehicle, or comprised in, on or connected, in use, to an exhaust system of the vehicle; wading detection means configured to detect a wading depth and to detect a wading condition corresponding to a detected wading depth that exceeds a predetermined wading depth and an end of the wading condition corresponding to the detected wading depth becoming less than the predetermined wading depth; an input means for receiving one or more signals from the wading detection means; and a processor operatively connected to the audible output means and to the input means, wherein the processor is configured to deactivate, in use, the audible output means on or after receipt of the one or more signals from the wading detection means corresponding to the wading detection means detecting or anticipating the wading condition.

2. A system according to claim 1, wherein the processor is configured to reactivate, in use, the audible output means on or after receipt of one or more signals from the wading detection means corresponding to detection, by the wading detection means, of an end of the wading condition.

3. A system according to claim 2, wherein the processor is configured to reactivate, in use, the audible output means after a predetermined period of time after detection by the wading detection means of the end of the wading condition.

4. A system according to claim 1, wherein the audible output means comprises one or more speakers.

5. A system according to claim 4, wherein the audible output means comprises two or more speakers, wherein the processor is configured to deactivate, in use, a first one of the speakers on or after detection or anticipation by the wading detection means of a first wading depth and to deactivate a second one of the speakers on or after detection or anticipation by the wading detection means of a second wading depth.

6. A system according to claim 5, wherein the processor is configured to reactivate, in use, the first speaker on or after detection by the wading detection means of a depth less than the first wading depth and to reactivate the second speaker on or after detection by the wading detection means of a depth less than the second wading depth.

7. A system according to claim 1, wherein the wading detection means is operatively connected to the input means.

8. A system according to claim 1, wherein the wading detection means comprises at least: a sensor responsive to contact with water or a sensor operable to sense water by at least one of transmission and reflection of a waveform or a camera detector or a computer vision apparatus or a geospatial positioning means.

9. A vehicle comprising an externally mounted active noise system according to claim 1, and wherein the wading detection means is operatively connected to the input means of the active noise system.

10. A method of protecting an active noise system comprising audible output means, wherein the audible output means is mounted to an underside of a vehicle, or comprised in, on or connected, in use, to an exhaust system of the vehicle, the method comprising: detecting a wading depth; detecting or anticipating a wading condition corresponding to the detected wading depth exceeding a predetermined wading depth; deactivating the audible output means of the active noise system when or after the wading condition is detected or anticipated; detecting an end of the wading condition corresponding to the detected wading depth becoming less than the predetermined wading depth; and reactivating the audible output means when or after the end of the wading condition is detected.

11. A method according to claim 10, further comprising reactivating the audible output means after a predetermined period of time after the end of the wading condition is detected.

12. A method according to claim 10, wherein the detecting or anticipating the wading condition comprises detecting or anticipating a wading depth and wherein the deactivating the audible output means occurs if the detected or anticipated wading depth exceeds a predetermined wading depth.

13. A method according to claim 12, comprising monitoring the wading depth continuously or intermittently.

14. A method according to claim 12, comprising monitoring the wading depth intermittently.

15. A non-transitory computer readable medium including program code, when executed by a processor, causing the processor to perform the method of claim 10.

16. A controller comprising the computer readable medium of claim 15.

17. A non-transitory computer readable medium having a program stored thereon, where the program, when executed by a computer, causes the computer to perform the method of claim 10.

18. An active noise system for external use on a vehicle, the system comprising: audible output means mounted to an underside of the vehicle, or comprised in, on or connected, in use, to an exhaust system of the vehicle, the audible output means comprising two or more speakers; wading detection means configured to detect a wading depth and to detect a wading condition corresponding to a detected wading depth that exceeds a predetermined wading depth and an end of the wading condition corresponding to the detected wading depth becoming less than the predetermined wading depth; an input means for receiving one or more signals from the wading detection means; and a processor operatively connected to the audible output means and to the input means, wherein the processor is configured to deactivate, in use, the audible output means on or after receipt of the one or more signals from the wading detection means corresponding to the wading detection means detecting or anticipating the wading condition, wherein the processor is configured to deactivate, in use, a first one of the speakers on or after detection or anticipation by the wading detection means of a first wading depth and to deactivate a second one of the speakers on or after detection or anticipation by the wading detection means of a second wading depth.

19. A system according to claim 18, wherein the processor is configured to reactivate, in use, the first speaker on or after detection by the wading detection means of a depth less than the first wading depth and to reactivate the second speaker on or after detection by the wading detection means of a depth less than the second wading depth.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a schematic representation of a vehicle incorporating an active noise system and a wading detection system in accordance with an embodiment of the invention; and

(3) FIG. 2 is a side view of the vehicle of FIG. 1 illustrating two predetermined wading depths.

DETAILED DESCRIPTION

(4) A vehicle in accordance with an embodiment of the invention is described herein with reference to the accompanying FIGS. 1 and 2.

(5) With reference to FIG. 1, there is provided a series hybrid-electric vehicle 1 that includes an internal combustion engine (ICE) 10, an electric machine (EM) 11, which is integrated as a motor/generator a second electric machine and associated driveline (not shown) are used to drive the wheels in this embodiment. The vehicle 1 also includes a body 2 with front wheels 20 and rear wheels 21, a wading detection system 3 and an active noise system 4.

(6) The ICE 10 and EM 11 are arranged to be able to provide electrical energy to charge the battery 12. The battery 12 is able to then power the second motor to deliver torque individually to a driveline (not shown) which ultimately provides torque to the rear wheels 21 of the vehicle 1.

(7) In other vehicles having a parallel hybrid configuration (not shown), the ICE 10 has a crankshaft drivable connection to an EM 11 input, the output of the EM 11 drivingly connects to the input of a transmission and driveline (not shown). In this way a parallel architecture is able to drive mechanical power from the ICE 10, through the transmission and driveline (not shown) to drive the vehicle and it is optional for the EM 11 to either add motive torque to the connected transmission or to take torque from the transmission to regenerate electrical power back into the battery, as is known by persons skilled in the art of hybrid vehicles.

(8) The inventive concept could also be used in conventional non hybrid vehicle architects where exhaust/vehicle noise modification is required.

(9) The various states of use of the combination of the ICE 10, the EM 11 and the battery 12 are controlled by a hybrid controller 13 of the vehicle 1. The hybrid controller 13 may be part of a larger vehicle electronic control unit (ECU), or may be a separate or otherwise integrated ECU, module, or other electronic or computer circuit or program.

(10) Such hybrid electric vehicles, and various alternative embodiments, as well as their use and control systems, are known in the prior art and will not be described further herein.

(11) In at least one drive mode, the vehicle may be provided with motive torque by the EM 11 whilst the ICE 10 is inactive. In at least one drive mode, the vehicle may be in motion whilst the ICE 10 is inactive and the EM 11 may not be supplying torque, or may indeed be supplying an effectively negative torque by acting as a generator.

(12) The ICE 10 produces exhaust gases, which pass through an exhaust system 14 of the vehicle. The exhaust system 14 includes a front section 15 with an exhaust manifold 15a, a centre section 16 with a centre box 16a and a rear section 17 with a rear box 17a. The skilled person will be familiar with such exhaust systems, which will not be described further herein.

(13) The wading detection system 3 includes ultrasonic sensors 30, 31, 32, 33 of the kind used for determining parking distances, which are all operatively connected to a wading detection controller 34. The sensors 30, 31, 32, 33 include lower and upper front sensors 30, 31 and lower and upper rear sensors 32, 33. The lower front sensor 30 is mounted in the front bumper ahead of the front wheels 20 and the upper front sensor 31 is mounted to the front of the vehicle 1 above the lower front sensor 30. Similarly, the lower rear sensor 32 is mounted to the rear bumper behind the rear wheels 21 and the upper rear sensor 33 is mounted to the rear of the vehicle 1 above the lower rear sensor 32.

(14) As shown more clearly in FIG. 2, the lower front sensor 30 has an output cone 30a diverging from the sensor 30 in a forward horizontal direction with respect to the front of the vehicle 1. Similarly, the lower rear sensor 32 has an output cone 32a diverging from the sensor 32 in a rearward horizontal direction with respect to the rear of the vehicle 1. The upper front sensor 31 has an output cone 31a diverging from the sensor 31 in a forward, but downward direction with respect to the front of the vehicle 1. The upper rear sensor 33 also has an output cone 33a that diverges from the sensor 33 in a rearward, but downward direction with respect to the rear of the vehicle 1.

(15) The lower sensors 30, 32 both transmit and receive ultrasonic signals to detect obstructions in the normal way, while the upper sensors 31, 33 both transmit and receive ultrasonic signals reflecting from the ground surface G. If immersed, the response of the sensors 30, 31, 32, 33 changes, thereby enabling their use to detect wading. Specifically, the response may for example exploit the different signal propagation speed for water and air, or the different diaphragm settling time for air and water immersion. The upper, downward facing sensors 31, 33 also receive ultrasonic signals reflected from the surface of water, and can thus be used to indicate a depth of water since the mounting location on the vehicle is known in relation to ground level, or can be interpolated from a suspension height sensor of a variable height suspension. In addition, these sensors 31, 33 allow detection for both forward and rearward vehicle motion, and can give an indication of inclination.

(16) Other means of detecting wading and/or depth of wading may be used.

(17) The vehicle 1 is also equipped with an active noise system 4 comprising a controller 40, speakers 41, 42 and a noise sensor 43. The controller 40 includes an input 40a that is connected to and receives signals from the wading detection controller 34 indicative of a measured wading depth. The speakers 41, 42 are located at different vertical positions as shown more clearly in FIG. 2. The noise sensor 43 is operable to detect and measure noise generated by the exhaust system 14 and provides a reading to the controller 40. The controller 40 is configured to generate a control signal to the speakers 41, 42 which may then act to modify the exhaust noise emitted from the vehicle 1. Such modification may correspond to a noise-cancelling of all or part of the noise, or may be an enhancement of all or part of the noise. Such systems when acting in this way are in general known to those skilled in the art.

(18) In embodiments, the active noise system 4 may be used to alert pedestrians when the vehicle 1 is powered by the EM 11 with the ICE 10 inactive or when both the EM 11 and the ICE 10 are inactive, for example in a coasting situation. In such situations, the active noise system controller 40 receives a signal from the hybrid controller 13 indicating that the ICE 10 is inactive, but that the vehicle 1 is in motion. The active noise system controller 40 then outputs a control signal to the speakers 41, 42, causing them to emit a noise signal. This noise signal is largely similar to the noise that might be expected of an ICE 10. In embodiments, the proximity of at least one of the speakers 41, 42 to the centre exhaust box 16a causes the exhaust box 16a to reverberate and increase the intensity or alter the tone of the noise emitted by the speakers 41, 42. In embodiments, the noise emitted and/or thus created by the speakers 41, 42 themselves or in combination with the exhaust system 14 may be modulated so as to vary appropriately with the speed of the vehicle 1.

(19) The active noise system 4 may additionally or alternatively be configured to enhance the noise produced by the exhaust system 14, for example where a sport mode is enabled and it is desirable to produce a predetermined noise profile. It is also envisaged that the active noise system 4 may be configured to suppress exhaust noise in order to provide a quiet luxury driving experience for drivers or passengers.

(20) In this embodiment, the wading detection system 3 is configured to detect a wading situation using the upper, downward facing sensors 31, 33. On detection of a wading situation, the wading detection controller 34 determines both the wading depth and the rate of change of the wading depth over time using the ultrasonic signals reflected from the surface of water and detected by the upper, downward facing sensors 31, 33. Based on these values, the wading detection controller 34 anticipates a first predetermined wading depth W.sub.1 at which the water will come into contact with the lower speaker 41 and, in response thereto, the wading detection controller 34 sends a signal to the active noise system controller 40, which disables the lower speaker 41. If the wading depth increases, the lower sensors 30, 32 are submerged, providing a second indication, to be used in combination with the depth measured by the upper sensors 31, 33, that a second predetermined wading depth W.sub.2 has been reached. The wading detection controller 34 then sends a signal to the active noise system controller 40, which disables the upper speaker 42.

(21) Thus, the aforementioned risk of damage to the speakers 41, 42 that would otherwise result from their operation in water is prevented. Deactivation of the speakers 41, 42 may comprise electrically isolating the speakers 41, 42. Additionally or alternatively, deactivation of the speakers 41, 42 may simply involve the active noise system controller 40 operating on a condition of not supplying signals thereto.

(22) When the vehicle 1 exits the body of water and the detected water level drops below the second predetermined wading depth W.sub.2, the wading detection system 3 sends a further signal to the active noise system controller 40, which reactivates the upper speaker 42 after a predetermined period of time, five minutes in this embodiment. Similarly, when the detected water level drops below the first predetermined wading depth W.sub.1, the wading detection system 3 sends a yet further signal to the active noise system controller 40, which reactivates the lower speaker 41 after a predetermined period of time, also five minutes in this embodiment. The purpose of the delay is to ensure that any water surrounding the speaker 42 has been drained off. It will be appreciated that five minutes is purely illustrative and that the actual delay may be more or less than this value. It is also envisaged that one or more other factors may be considered. For example, the speed of the vehicle 1 and measured wading depth may be used to determine a situation in which one or each speaker 41, 42 is likely to be exposed to excessive water, in which case reactivation may be delayed. Other situations are also envisaged and would be appreciated by the skilled person.

(23) It will be appreciated that the speakers 41, 42 need not be located at different vertical heights. It is expressly envisaged that both speakers 41, 42 may be located at the same height, for example on opposite sides of the centre box 16a of the exhaust system 14. In such cases, there may only be a single predetermined wading depth W.sub.1. Additionally or alternatively, the active noise system 4 may incorporate additional speakers and/or other audible devices, such as one or more audible alarms or sirens or horns or other such devices, which may be located at different positions. In such cases, there may be three or more predetermined wading depths. The speakers 41, 42 may be separate from the exhaust system 14 and/or may be mounted underbody in any suitable position where there is sufficient space. The speakers 41, 42 may act as a muffler and/or may be housed in an exhaust muffler.

(24) Similarly, the wading detection system 3 may additionally or alternatively include sensors 30, 31, 32, 33 of a different design, for example one or more camera detectors or computer vision apparatus. In embodiments, the wading detection system 3 incorporates a geospatial positioning system and may also include a communication means for receiving information regarding water levels and/or precipitation levels associated with one or more geospatial locations. In such embodiments, the wading detection system 3 may incorporate one or more algorithms operable to anticipate a wading condition based at least in part on information received by the communication means.