WO2013030729A2

WO2013030729A2 - Method and system for controlling noise level in an automotive electronic device

Info

Publication number: WO2013030729A2
Application number: PCT/IB2012/054267
Authority: WO
Inventors: Fangzhong Shen
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2011-08-26
Filing date: 2012-08-23
Publication date: 2013-03-07
Also published as: WO2013030729A3

Abstract

The invention generally relates to a method for controlling noise level made by a device in an automobile. The method includes: detecting (210, 310) an ambient noise level in the automotive; and controlling (230,240;320,330,340) the working status of the device in an automotive such that the noise level generated by the device is lower than the ambient noise level by a predefined value. The invention also generally relates to a system for controlling for controlling noise level made by a device in an automobile. The system includes a detector (120) for detecting an ambient noise level in the automotive; and a controller (130) for controlling the working status of the device such that the noise level generated by the air purifier is lower than the ambient noise level by a predefined value. Thus, some annoying noise can be effectively masked.

Description

METHOD AND SYSTEM FOR CONTROLLING NOISE LEVEL IN AN AUTOMOTIVE ELECTRONIC DEVICE

FIELD OF THE INVENTION

The invention generally relates to the field of automotive electronic devices, and particularly relates to a system and a method for controlling noise level made by a device, such as an air purifier in an automobile.

BACKGROUND OF THE INVENTION

In order to improve air quality in the cabin of an automobile, air purifiers can be employed. Some air purifiers use an impeller driven by a motor for inhaling or exhaling air, which is forced through a filter. Thereby, fine particles and/or chemical gases are filtered, and clean air is generated there from.

In air purifiers using an impeller motor, the smaller the impeller is, the higher rotation speed is required to generate the same air flow. Due to typical space limitations in cars, smaller impellers are preferred while significant air flow is expected still, which may result in an annoying noise level caused by the impeller and /or a motor and therefore affect the mood of the driver and passenger. In addition to air purifiers, automobiles may employ other devices generating unpleasant noise when the air purifier is working.

Thus, there is a need to limit or eliminate the unpleasant noise generated by a target device such as an air purifier.

SUMMARY OF THE INVENTION

Due to the disadvantages as mentioned above, the invention implements such a mechanism that the noise level generated by a target device such as an air purifier in an automotive is tuned to be lower than the ambient noise in an automotive with a noise gap, such that the target noise from the air purifier is substantially masked or covered by the ambient noise. According to some embodiments of the invention, a method for controlling the noise level made by a target device in an automotive is provided, the method comprises the steps of: detecting an ambient noise level in the automotive; and controlling the working status of the target device in an automotive such that the noise level generated by the target device is lower than the ambient noise level by a predefined value.

In some embodiments of the invention, the target device is an air purifier which comprises an impeller; and the predefined value is of about 17dB, of course which can be larger than 17dB. Especially, in these embodiments, the step of controlling the working status of the air purifier comprises controlling the rotation speed of the impeller of the air purifier. And more especially, the step of controlling the rotation speed of the impeller of the air purifier comprises: i) decreasing the rotation speed of the impeller when the detected ambient noise level decreases; and ii) increasing the rotation speed of the impeller when the detected ambient noise level increases.

Wherein, in some embodiments, the rotation speed of the impeller of the air purifier is increased to a higher level with a time delay when the ambient noise level in the automotive increases.

According to some embodiments of the invention, a system for controlling noise level made by a target device in an automotive is provided, which comprises: a detector for detecting an ambient noise level in the automotive; and a controller for controlling the working status of the target device such that the noise level generated by the air purifier is lower than the ambient noise level by a predefined value.

In some embodiments, the predefined value is of about 17dB and the target device is an air purifier which comprises an impeller. In these embodiments, especially, the controller is arranged to control the rotation speed of the impeller of the air purifier. More especially, the controller is arranged to: -decrease the rotation speed of the impeller when the detected ambient noise level decreases; and -increase the rotation speed of the impeller when the detected ambient noise level increases.

In some embodiments of the system, the detector is positioned substantially far away from the target device. Especially, as for an air purifier, the detector is far away from a rotation motor of the air purifier, such as from the impeller and/or motor thereof.

According to another aspect of the invention, an automotive air purifier comprising a system for controlling the noise level made by a target device in an automotive as defined above is provided.

According to another aspect of the invention, a vehicle provided with an automotive air purifier as described above or with a system for controlling the noise level made by a target device in an automotive as described above is provided.

According to another aspect of the invention, a computer program product which is executed by a processor or a controller to perform the method as above is provided.

By the invention, the noise level, especially the unpleasant noise level is kept in a low level and masked by ambient noise level which maybe not avoidable completely, which thus renders a more pleasing driving circumstance in a car.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Figure 1 illustrates a block of the structure of an air purifier and a system for controlling the working status of a target device such as an air purifier according to some embodiments of the invention.

Figure 2 illustrates a flow chart of a process of controlling the air purifier according to some embodiments of the controlling process.

Figure 3 illustrates a flow chart of a process of controlling the air purifier according to some embodiments of the controlling process. DETAILED DESCRIPTION OF THE EMBODIMENTS

Generally, the invention is based on the insight that a human's ear has an auditory masking effect. For example, when the ambient noise level is higher than the target noise level by a noise gap such as about 17dB, the target noise level will be substantially unnoticeable, in other words, will be hidden under ambient noise.

When a car is running on road, there will be much ambient noise, such as, a level of 66-74 dBA during driving at constant speed of 70km/hr on concrete road. For a driver or a passenger in an automobile, the ambient noise sources can be very diversified, including, for example, tire noise, engine noise, air conditioner blower noise, music radio noise, BSR noise (buzz, squeak, rattle) of the cabin compartment during driving, human voice, outdoor noise, etc.

As for a target unit, such as an air purifier or other electronic device, it will also generate unpleasant noise from its components, such as an internal impeller or a motor. The target noise generated by a device such as an impeller, usually is annoying, and is desired to be masked or covered.

Accordingly, some embodiments of the invention implement a mechanism such that the target noise (e.g., the noise from a target device such as an air purifier) is substantially masked or covered by using the ambient noise of an automobile.

FIG. 1 illustrates a block diagram of the structure of a system 110 for controlling the working status of an air purifier in an automotive according to some embodiments. The system 110 includes a noise detector 120 (e.g., an acoustic sensor) and a control 130 (e.g., a micro-controller unit MCU). The noise detector 120 can detect the ambient noise perceived by the driver and/or passenger(s) in an automobile, and can generate one or more signals indicative of the ambient noise level. The controller 130 is coupled with the noise detector 120 to receive the signal(s), and coupled with an air purifier 140 (or other noise-producing device) to control its working status (e.g., its volume). In addition, the controller 130 can include an A/D converter (not shown) for converting sound analog signals into a digital signal, and an integrating unit for deriving the sound level (e.g., by integrating the digital noise signals in a moving time window), which is easily understood by the technicians and need not to be further detailed. In some embodiments, the A/D converter can be integrated with the noise detector 120.

In some embodiments, the detector 120 is positioned relatively far away from the air purifier 140, especially from the impeller 150, the rotation motor (not shown), or other noise-producing components thereof in the air purifier 140 or other noise-producing component as the case may be.

The controller 130 can adjust the operation of air purifier 140, such as, for example, the rotation speed of the impeller 150, on the basis of the detected ambient noise level. Due to the principle of auditory masking, the noise from the air purifier 150 can be tuned to be lower than the ambient noise with a noise gap such as, for example, about 17 dB. In some embodiments, the noise gap can be larger than 17 dB.

In general, the target noise levels, e.g., the noises originating from the air purifier or other noise-producing component, are substantially dependent on the rotation speeds of the impeller(s), as is illustrated in the following formula:

Target Noise Level = Target Rotation Speed * K (1) wherein K is a variable or a constant coefficient. Equation (1) can be also expressed as:

Target Rotation Speed = Target Noise Level / K (2) In some embodiments, the relationship(s) (e.g., the values for the coefficient K) between the target rotation speed and the target noise level for an air purifier or other noise-producing device can be predefined and/or pre-stored in a memory unit (e.g., ROM) within or coupled to controller 130.

Thus, in some embodiments where the the Target Noise Level is controlled to be < ambient noise level - noise gap (e.g., 17 dB), it can be derived that:

Target Rotation Speed < (Ambient Noise Level - Noise Gap) / K (3)

Thus, the controller 130 can be arranged to control the target rotation speed of an air purifier according to the above formula (3) by use of the ambient noise levels detected by the detector 120 and the pre-stored values for K as well as a pre-stored noise gap value such as 17 dB.

Figure 2 illustrates a flow chart of a process of controlling the air purifier (or other noise-producing device) implemented by the controller 130 as mentioned above according to some embodiments of the invention:

In step 210, after the startup of the operation of an air purifier in an automotive, the detector 120 (e.g., an acoustic sensor), begins to detect the ambient noise level and generates corresponding signals indicative of the ambient noise level.

In step 220, the signals are sampled and converted from analog signals into digital signals by a sampler and A/D converter, which can be integrated in the controller 130, the detector 120, or other single member. In alternative or supplemental embodiments, the controller can include analog signal processing circuitry for generating a control signal to control the noise-producing component 140.

In step 230, the controller 130 (e.g., a processor) determines the target rotation speed value of the impeller 150 of an air purifier 140 (or other value associated with a noise-producing device 140) on the basics of the digital and/or analog signals representing the ambient noise levels. Determining the target rotation speed value can include determining the ambient noise level and using the values for noise gap and K, wherein determining the ambient noise level can include integrating the signals sampled and converted in step 220 and forming a value representing the ambient noise level.

Furthermore, the controller 130 can determine if the current rotation speed needs to be altered by comparing the target rotation speed and the current rotation speed. The current rotation speed can be obtained by a sensor and/or from a memory unit. The controller 130 can determine to increase the rotation speed level when the target noise level is higher than the current noise level, to decrease the rotation speed level when the target noise level is lower than the current noise level, and/or to maintain the current rotation speed level when the target noise level is equal or equivalent to the current noise level. In some embodiments, when the controller 130 determines to decrease the rotation speed level, it can immediately send instructions to the air purifier or send after a time delay. When the controller 130 determines to increase the rotation speed level, it can send the instructions immediately or after a time delay.

In step 240, the air purifier 140 alters or maintains the current rotation speed level according to the instructions from the controller. It is easily understood to the skilled technicians that the instructions from the controller 130 can be interpreted into actuating signals for the rotation motor of the air purifier. In some embodiments, the instructions from the controller 130 can include a pulse width modulation (PWM) signal.

The rotation speeds of an impeller of an air purifier can be divided into multiple levels. In some embodiments, the speeds are divided into three levels: SPD H, SPD M, SPD L, each corresponding to a predetermined rotation speed. In general, any number of rotation speed levels is possible and adoptable. Figure 3 illustrates a flow chart of a process of controlling the noise-producing device 140 according to some embodiments of the controlling process.

In step 310, after the initialization of the air purifier, the state of the device enters into a default level. For example, the rotation speed of the air purifier goes into a default level such as the middle level SPD M.

In step 320, the controller 130 receives signals from the detector 120 and determines if the current rotation speed level of the air purifier needs to be elevated into a higher level, or to be lowered to a lower level, or to be maintained at current level, by determining the target rotation speed level and comparing it with the current rotation speed level.

In some embodiments, the determination of transitioning between the SPD H, SPD M and SPD L states is made by determining whether a threshold condition has been met. In the case of three states, two threshold values can be provided (e.g., THRES LM and THRES HM). In general, if there are n number of states, then a system can have n-1 threshold values. For example, if the system is in the SPD L state, then the controller can compare the measured noise level from the detector 120 with the THRES LM value (e.g., the threshold value between the "L" and "M" states). If the measured noise level is less than the THRES LM value, then the state of the device 140 does not change. However, if the measured noise level is greater than or equal to/greater than THRES LM, then the controller 130 can signal to device 140 to transition to the SPD M state. Similar comparisons can be made for transitioning up to higher states or transitioning down states.

In some cases, the measured noise level may transition frequently just around one of the threshold values. In some embodiments, a delaying-action factor value (DELTA) can be used to obviate such frequent transitions. For example, rather than changing states immediately upon a determination that the ambient sound level is above or below a threshold between two states (e.g., THRES LM between states SPD L and SPD M), the transition will only occur if the measured noise level is at least DELTA above or below the threshold. For example, if the system is in the SPD L state, then the controller can compare the measured noise level from the detector 120 with THRES LM + DELTA. If the measured noise level is greater than or equal to/greater than THRES LM + DELTA, then the controller 130 can signal to device 140 to transition to the SPD M state. In some embodiments, the DELTA value can be used only in all upward transitions, only in all downward transitions, both upward and downward transitions, or any combination of transitions. In some embodiments, the DELTA value can be different between upward and downward transitions.

Next, if the controller 130 determines in step 320 that the current speed level needs to be elevated to a higher level, the controller 130 sends instructions to the air purifier after an optional time delay as shown in step 321 and then make the air purifier to change its rotation speed in step 330. Meanwhile, if it determines in step 320 that the speed level needs to be decreased, the controller sends instructions immediately and then make the air purifier to lower the rotation speed level in step 340. After the alteration of rotation speed level, the controller 130 goes back to the step 320 and continue the process. In some embodiments, transitions between states at steps 330 or 340 can occur immediately, or can be smoother (e.g., via tuning the PWM signal in granular steps instead of a sudden change).

Meanwhile, if it determines in step 320 that the current speed level needs to be maintained, the controller 130 keeps the current rotation speed level and goes back to the step 320. In general, the processes illustrated in FIGS. 2-3 can be employed with any noise-producing device 140 by controlling a signal value that affects the amount of noise produced by a component 150. Accordingly, the annoying noise by some electric devices in an automobile can advantageously be reduced and hidden by the ambient noise.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. For instance, the invention is not limited to be implemented in an air purifier, but can be used for other electronic devices that generate noise in an automobile, such as an air-conditioner, an AJC blower, an in-car audio video multimedia system, etc. In addition, the processor can be a general microprocessor being programmed with software, or be in the form of hardware, firmware.

In the claims, use of the verb "to comprise" and its conjugations, does not exclude the presence of other elements or steps, and the article "a", or "an" preceding an element does not exclude the presence of a plurality of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

What is claimed is:

1. A method for controlling noise level made by a target device in an automobile, the method comprising:

a) detecting (210, 310) an ambient noise level in the automobile; and

b) controlling (230,240;320,330,340) the working status of the target device such that the noise level generated by the target device is lower than the detected ambient noise level by at least a predefined value.

2. The method as claimed in claim 1, wherein the target device is an air purifier comprising an impeller, and the predefined value is at least 17dB.

3. The method of claim 2, wherein the step b) further comprises:

controlling the rotation speed of the impeller of the air purifier.

4. The method of claim 3, wherein the step of controlling the rotation speed of the impeller of the air purifier comprises:

i) decreasing (340) the rotation speed of the impeller when the detected ambient noise level decreases; and

ii) increasing (330) the rotation speed of the impeller when the detected ambient noise level increases.

5. The method as claimed in claim 1 further comprising comparing the detected ambient noise level with one or more predetermined threshold values associated with the current working status of the target device, wherein controlling (230,240;320,330,340) the working status of the target device comprises changing the current working status if the detected ambient noise level satisfies a predetermined criterion with respect to the one or more predetermined threshold values.

6. The method as claimed in claim 4, wherein the rotation speed of the impeller of the air purifier is increased to a higher stage with a time delay when the ambient noise level in the automotive increases.

7. A system for controlling noise level made by a target device in an automobile, comprising: an ambient noise detector (120); and

a controller (130) coupled to the target device and to the ambient noise detector (120), the controller (130) configured to control the working status of the target device such that the noise level generated by the target device is lower than the ambient noise level by at least a predefined value.

8. The system as claimed in claim 7, wherein

the target device is an air purifier which comprises an impeller (150); and

the predefined value is at least 17dB.

9. The system as claimed in claim 8, wherein the controller (130) is configured to:

control the rotation speed of the impeller (150) of the air purifier (140).

10. The system as claimed in claim 9, wherein the controller (130) is further configured to: decrease the rotation speed of the impeller when the detected ambient noise level decreases; and

increase the rotation speed of the impeller when the detected ambient noise level increases.

11. The system as claimed in claim 8, wherein

the ambient noise detector (120) is positioned substantially far away from a rotation motor and/ or the impeller of the air purifier (140).

12. An automotive air purifier comprising a system as claimed in any of preceding claims 7-11.

13. A vehicle provided with an automotive air purifier as claimed in claim 11 or with a system as claimed in any of preceding claims 7-11.

14. A computer program product which is executed by a processor or a controller to perform the method as claimed in any of claims 1-6.