Claims:We claim:

1. A laser-based advanced Pass-By Noise sensing and measurement system for reducing the pass-by noise in automotive vehicles, the system is installed on a pass-by noise test track and comprises a wireless data acquisition system including:

- at least one master system fitted inside the vehicle,
- at least one ICP accelerometer connected to the master system,
- at least two ICP microphones placed at a predetermined distance on either side of the test track at the mid-point thereof,
- at least two slave systems for acquiring data from the ICP microphones and ICP accelerometers (high speed sensors) connected to the master system,
- at least one slave system for gathering and transmitting triggering signal and to collect and transmit the track-distance and vehicle-speed to the master system,
- at least one laser distance meter,

wherein the master system uses the data transmitted by the slave systems for generating the accurate position of the automobile by means of the laser distance meter for enabling the driver to accurately press the throttle at the start line of the test track and to release the throttle at stop line of the test track by means of audio communications.

2. Pass-by noise sensing and measuring system as claimed in claim 1, wherein the two slave systems are disposed on either side of the test track are first slave system and second slave system and a third slave system is placed substantially close to the laser distance meter (LDM) near the starting point on the test track.

3. Pass-by noise sensing and measuring system as claimed in claim 1, wherein the system includes a plurality of DAQPORT boards, a computing device and respective plurality of Wireless LAN adapters.

4. Pass-by noise sensing and measuring system as claimed in claim 1, wherein the master system includes at least one DAQPORT board to acquire data over multiple audio channels and also to acquire other vehicular parameters such as engine RPM, engine temperature, vehicle temperature, throttle position, vibration, acceleration, vehicle speed, vehicle position, displacement etc.

5. Pass-by noise sensing and measuring system as claimed in claim 1, wherein the master system includes eight dynamic channels and four slow-speed channels.

6. Pass-by noise sensing and measuring system as claimed in claim 1, wherein each slave system includes at least one respective DAQPORT board to acquire audio data, to receive synchronization triggering signals from the master system in the vehicle and to store single channel audio data only.

7. Pass-by noise sensing and measuring system as claimed in claim 1, wherein the laser distance meter (LDM) is a laser diode based range finder.

8. Pass-by noise sensing and measuring system as claimed in claim 2, wherein LDM is placed substantially close to the third slave system and all the signals generated between the starting point and the stopping point are acquired simultaneously by means of trigger through laser from the master system and first and second slave systems.

9. Method of sensing and measuring pass-by noise with the pass-by noise sensing and measuring system as claimed in claim 1 to 8, wherein the method comprises the following method steps:

(g) receiving synchronization triggers from the master system through laser source in the vehicle,

(h) acquiring audio data from the ICP microphones disposed on both sides of the test track via a respective slave system

(i) acquiring other vehicular parameters like engine RPM, engine temperature, vehicle temperature, throttle position, vibration, acceleration, vehicle speed, vehicle position via respective sensors connected to the master system;

(j) simultaneously acquiring all the signals generated between the starting point and the stopping point from master system and first and second slave systems by means of trigger through laser through laser on entering the test area;

(k) acquiring and transmitting the triggering signal and collecting and transmitting the track-distance and vehicle-speed by means of the third slave system to the master system;

(l) receiving the signals from all systems into the master system by means of wireless router;

wherein the measured signals are processed in the master system for analyzing the sound pressure levels and accelerations in the vehicle in the test area close to ICP microphones and a correlation between these signals is established with the measured pass-by noise levels to identify the main noise contributors.

10. Method as claimed in claim 9, wherein by measuring the transfer function between highest sound pressure vehicle locations on the pass-by noise test track by means of the ICP microphones placed at a prescribed distance outside from the test track and predicting the exact contributing factors of noise sources by multiplying transfer function with the operational sound pressure, which can be used by the vehicle driver for precisely pressing the throttle exactly at the start line on the test track and releasing the throttle at the stop line on the test track by audio communications, such as head phones.

Dated: this 05th day of November, 2015. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT , Description:FIELD OF INVENTION

The present invention relates to a noise, vibration and harshness (NVH) reducing system for an automobile. In particular, the invention relates to an advanced pass-by noise system for an automobile. The present invention also relates to a method for sensing and measuring pass-by noise by means of an advanced pass-by noise system in accordance with the present invention.

BACKGROUND OF THE INVENTION

At present, the stringent noise legislations and the increased awareness regarding NVH amongst the customers are posing greatest challenges for a full NVH development in automotive vehicles. Further, the certification of vehicle noise emissions for passenger vehicles, motorcycles and light trucks is generally achieved by measuring external sound levels according to the procedure defined by international standards, e.g. ISO362/IS3028/SAEJ1470.

The current procedure is based on carrying out a pass-by test, wherein the overall noise levels are measured during wide-open throttle accelerations in 2nd and 3rd gears for 5-speed gearbox vehicles. As shown in Figure 1, the vehicle approaches the test zone at constant approach speed until it reaches line A-A’. At this position, the driver suddenly opens the throttle wide and accelerates until the vehicle reaches line B-B’. The maximum weighted overall sound pressure levels are measured at about 7.5 m from the centre line P-P’ of the test track, i.e. at points M1 and M2 by using sound level meters provided on both side of the test track and then averaged over a number of passes.

DISADVANTAGES WITH THE PRIOR ART

Today, most of vehicle manufactures are using traditional sound level meter, as explained above, to measure the Pass-by Noise levels of the vehicle. This measurement process gives only the absolute values of the Pass-by noise. Moreover, the current method of using sound level meter to obtain the Pass-by noise levels for vehicles gives a variation in the range of ± 0.5 dB.

If the vehicle does not meet the noise level targets, the refinement of NVH values is to be achieved for all sources for meeting the applicable noise regulations.

In a typical existing vehicle Pass-By Noise testing system by using radio microphones, a pair of photocells attached to inside of vehicle side window glass, one on either side. The lasers are aimed on these photocells at the starting point, midpoint and end point of the test track while the vehicle passes these points. The radio microphones are provided on either side of test track and radio receivers are provided inside vehicle cabin. An on-board data acquisition system is provided ideally inside the vehicle cabin. However, such system do not help in understanding the relative position of the vehicle with respect to the radio microphones for providing further insights about the dynamic characteristics.

Thus, for reducing the Pass-by noise levels, the dynamic NVH characteristics of the vehicle need to be understood to identify the major noise generating sources. The measurement using a conventional sound level meter also does not provide this information readily. Further, to meet the existing stringent noise legislative requirements, refinement of all vehicle noise sources is essential. The reduction in the unwanted noise emission in motor vehicles is not regulated only by the legislations, but is also an important concern for the automobile manufacturers for offering good quality vehicles to the customer to meet their ever-increasing demands regarding the NVH reduction.

Moreover, due to the stringent noise emission norms yet to be put in place in the coming years, the noise targets can be met only by the application of efficient NVH measurements and the latest testing technology for analyzing the spectral contributions of all the noise generating sources in the vehicle. It is also essential to understand the vehicle’s relative position with respect to the microphones placed around the test track for capturing the dynamic NVH characteristics as well. To overcome these problems, an advanced pass-by noise system is essential for vehicle NVH development.

Therefore, there is a long felt need for eliminating the disadvantages associated with the conventional pass-by NVH system for automotive vehicles. The laser-technology based pass-by NVH system configured in accordance with the present invention is advantageously deployed for this purpose.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide an advanced pass-by NVH system for an automotive vehicle.

Another object of the present invention is to provide an advanced pass-by NVH system which can conduct pass-by noise tests on all types of vehicles.

Still another object of the present invention is to provide an advanced pass-by NVH system to measure noise, vibration and harshness characteristics simultaneously.

Yet another object of the present invention is to provide an advanced pass-by NVH system to measure additional vehicle parameters, such as engine temperature, RPM, Throttle position, speed etc.

A further object of the present invention is to provide an advanced pass-by NVH system including a combination of master and slave units.

Still further object of the present invention is to provide an advanced pass-by NVH system for generating the accurate position of the vehicle.

These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an advanced pass-by noise system for an automobile. The system consists of a laser-based advanced Pass-By Noise sensing and measurement system for reducing the pass-by noise in automotive vehicles, the system is installed on a pass-by noise test track and comprises a wireless data acquisition system including:

- at least one master system fitted inside the vehicle,
- at least one ICP accelerometer connected to the master system,
- at least two ICP microphones placed at a predetermined distance on either side of the test track at the mid-point thereof,
- at least two slave systems for acquiring data from the ICP microphones and ICP accelerometers (high speed sensors) connected to the master system,
- at least one slave system for gathering and transmitting triggering signal and to collect and transmit the track-distance and vehicle-speed to the master system,
- at least one laser distance meter,

wherein the master system uses the data transmitted by the slave systems for generating the accurate position of the automobile by means of the laser distance meter for enabling the driver to accurately press the throttle at the start line of the test track and to release the throttle at stop line of the test track by means of audio communications.

Typically, the two slave systems are disposed on either side of the test track are first slave system and second slave system and a third slave system is placed substantially close to the laser distance meter (LDM) near the starting point on the test track.

Typically, the system includes a plurality of DAQPORT boards, a computing device and respective plurality of Wireless LAN adapters.

Typically, the master system includes at least one DAQPORT board to acquire data over multiple audio channels and also to acquire other vehicular parameters such as engine RPM, engine temperature, vehicle temperature, throttle position, vibration, acceleration, vehicle speed, vehicle position, displacement etc.

Typically, the master system includes eight dynamic channels and four slow-speed channels.

Typically, each slave system includes at least one respective DAQPORT board to acquire audio data, to receive synchronization triggering signals from the master system in the vehicle and to store single channel audio data only.

Typically, the laser distance meter (LDM) is a laser diode based range finder.

Typically, the laser distance meter (LDM) is placed substantially close to the third slave system and all the signals generated between the starting point and the stopping point are acquired simultaneously by means of trigger through laser from the master system and first and second slave systems.

In accordance with the present invention, there is also provided a method for sensing and measuring pass-by noise with the pass-by noise sensing and measuring system as claimed in claim 1 to 8, wherein the method comprises the following method steps:

(a) receiving synchronization triggers from the master system through laser source in the vehicle,

(b) acquiring audio data from the ICP microphones disposed on both sides of the test track via a respective slave system

(c) acquiring other vehicular parameters like engine RPM, engine temperature, vehicle temperature, throttle position, vibration, acceleration, vehicle speed, vehicle position via respective sensors connected to the master system;

(d) simultaneously acquiring all the signals generated between the starting point and the stopping point from master system and first and second slave systems by means of trigger through laser through laser on entering the test area;

(e) acquiring and transmitting the triggering signal and collecting and transmitting the track-distance and vehicle-speed by means of the third slave system to the master system;

(f) receiving the signals from all systems into the master system by means of wireless router;

wherein the measured signals are processed in the master system for analyzing the sound pressure levels and accelerations in the vehicle in the test area close to ICP microphones and a correlation between these signals is established with the measured pass-by noise levels to identify the main noise contributors.

Typically, by measuring the transfer function between highest sound pressure vehicle locations on the pass-by noise test track by means of the ICP microphones placed at a prescribed distance outside from the test track and predicting the exact contributing factors of noise sources by multiplying transfer function with the operational sound pressure, which can be used by the vehicle driver for precisely pressing the throttle exactly at the start line on the test track and releasing the throttle at the stop line on the test track by audio communications, such as head phones.

DESCRIPTION OF THE PRESENT INVENTION

Also new Pass By regulation procedure is getting updated in couple of years where vehicle acceleration at AA line, centre-line & BB line need to be captured for Pass By noise measurements.

To get the all the relevant information about vehicle noise sources, it is need to understand following major information’s:-

• Accurate vehicle approach & departure speed between 20m Pass-By noise track.
• Vehicle acceleration level.
• Engine rpm.
• Throttle position.
• Triggering for throttle operation (Press and release).
• Noise verves Pass-by track length, Noise verves Vehicle speed & Noise verses engine RPM.
• Noise Sources strength.
• To measure the transfer function.
• To accurately collect the all the relevant information from vehicle speed, outside microphones location as well as all vehicle NVH source strength simultaneously and accurately for very short time duration, preferably within 2 to 4 seconds.
• Readiness for future stringent noise norms.

These requirements can be measured by using commercially available Advanced Pass-By system (B&K, Muller BBM make*). The above system can be used to meet the challenges by quickly obtaining the certification for the permitted noise levels and furnishing insights into root cause of any problems.

This is done by measuring sound pressure levels and accelerations in the vehicle close to possible sound sources and correlating these signals with measured pass by noise levels to identify the main noise contributors.

Further, by measuring the transfer function between highest sound pressure vehicle location on the pass-by noise test-track and microphones kept 7.5 m outside and by multiplying the transfer function by operational sound pressure, it is possible to predict exact contributions of noise sources.

Today in commercial markets, advanced pass by noise full system is available for measuring and diagnosing the noise source. However, this system costs more than 1.4 cores. Moreover, these systems are based on GPRS transmitter and receiver based.

The present applicants have developed an advanced, however very cost-effective Pass-by noise system by using laser-Bluetooth interface technology for communication and data exchange. This Advance Pass-by noise system configured in accordance with the present invention is a laser-based technology used to conduct the pass-by trials.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1 shows the schematic layout of the conventional pass-by noise track.

Figure 2 shows the schematic layout of the advanced pass-by NVH system in accordance with the present invention configured for an automotive vehicle.

Figures 3a to 3c show an experimental set-up for the advanced pass-by noise measurement system of Figure 2.

Figure 4a shows different time signal representation which were acquired from the master system during the pass by noise trials.

Figure 4b shows different time signal representation which were acquired from the slave system during the pass by noise trials.

Figure 4c to 4f show the interpretation of results from the acquired time signals.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows the schematic layout of the conventional pass-by noise track. It shows a test-track TT, preferably of minimum 3m width and about 60m length and a substantially square area A-B-B’-A’ disposed midway around the test track (e.g. 20m x 20m). The test area is a minimum area covered with test road surface Amin marked in grey here. A pair of sound level meters at points M1 and M2 is placed at about 1.2m height from the test area and at about 7.5m from the centre-line of the test track TT on either side thereof. An automobile V approaches the test track TT travelling midway on the test track at a constant speed until it reaches line AA’. At this position, suddenly the throttle is opened wide by the driver and the automobile V is accelerated until it reaches line BB’. Maximum weighted overall sound pressure levels are measured by sound level meters at M1 and M2 and average value is obtained after passing the automobile V over the test track for a certain number of passes. However, in this conventional measurement technique, a variation of ±0.5dB is noticed and refinements are necessary, if noise level targets are not achieved within statutorily prescribed noise limits.

Figure 2 shows the schematic layout of the advanced pass-by NVH system in accordance with the present invention configured for an automotive vehicle. This advance Pass-by noise system is based on laser-based technology, which uses a wireless data acquisition system. It includes a master system MS and three slave systems SS1, SS2 and SS3 respectively. There is also one laser distance meter LDM and two ICP microphones MP placed on either side of the test track. The master system MS is fitted inside the automobile V to acquire the data from the ICP microphones MP and ICP accelerometers (high speed sensors) connected to the master system MS, which also includes 8 dynamic channels. There are also 4 slow speed channels to measure engine temperature, throttle position and engine RPM. Out of these three slave units SS1, SS2 and SS3, two slave units SS1 and SS2 have an input for acquiring data from the ICP microphones MP from outside these microphones and the third slave unit SS3 gathers and transmits the triggering signal and also collects and transmit the track-distance and vehicle-speed to the master system MS, which uses this data to generate the accurate position of the automobile V. Accordingly, the advantage of this laser distance meter LDM is that the driver is able to press the throttle exactly at the start line ST (AA’ in Figure 1) and release the throttle at stop line SP (BB’ in Figure 1) by audio communications (Head phones).

Figures 3a shows one of the three slave systems, two slave systems SS1 or SS2 are mounted on either side of the test track as shown in Figure 2 and have one input each to acquire the data from the microphone from one of the outside ICP microphones MP and the third slave system SS3 is placed close to the laser distance meter LDM, which gathers and transmits triggering signal and also gathers and sends back the track distance and vehicle speed to the master system MS for generating the accurate position of the vehicle. Accordingly, the vehicle driver can exactly press the throttle at the start line A-A’ and release the throttle at the stop line B-B’ by using audio communications (head phones).

Figures 3b shows the DAQPORT board configured to acquire data over multiple audio channels (up to six) as well to acquire other vehicular parameters such as Engine RPM, Engine temperature, Vehicle temperature, Throttle position, vehicle speed to furnish additional details. The master unit, which is located inside the vehicle, acquires the data from the ICP microphones MP and ICP accelerometers (high speed sensors) connected to it. There are 8 such high speed channels. It can also measure temperature, throttle position and engine RPM by using slow-speed channels. Master unit consists of 8 dynamic channels and 4 slow speed channels.

Figures 3c shows the of the laser distance meter LDM mounted adjacent the third slave system SS3 shown in Figure 2.

Figure 4a shows different time signal representation acquired from the master system MS during the pass-by noise trials.

Figure 4b shows different time signal representation acquired from the slave system SS1 and SS2 during the pass- by noise trials.

Figure 4c shows the interpretation of results obtained from the acquired time signals for distance, velocity and acceleration.

Figure 4d shows the interpretation of results obtained from the acquired time signals for comparing the pass-by noise v/s distance.

Figure 4e shows the interpretation of results obtained from the acquired time signals for comparing the pass-by noise v/s engine RPM.

Figure 4f shows the interpretation of results obtained from the acquired time signals for comparing the chassis-vibration v/s distance.

CONSTRUCTIONAL DETAILS FOR ADVANCED PASS BY NOISE SYSTEM

This system is a wireless data acquisition system. It is used for pass-by noise test for all types of vehicles. It is also meant to simultaneously measure noise, vibration and other vehicle parameters (e.g. engine temperature, RPM, throttle position, speed) to furnish additional details. It consists of one master and two slave units. The master unit housed inside the vehicle, acquires the data from the ICP microphones and ICP accelerometers (high speed sensors) connected to it.

There are eight (8) such high speed channels. It can also measure temperature, throttle position and engine RPM by using slow-speed channels. Master unit consists of eight (8) dynamic channels and 4 slow speed channels.

There are three slave units, two slave units will be having one input to acquire the data from the microphone from outside microphone and the other slave unit has gather and transmit the triggering signal as well as gathers and sends track distance and vehicle speed. This is for generating the accurate position of the vehicle.

The advantage of the laser distance meter is that the driver can exactly press the throttle at the start line (AA’) and release the throttle at stop line (BB’) by audio communications (Head phones).

DAQPORT board (Figure 3b) can configured to acquire data over multiple audio channels (up to six) as well to acquire other vehicular parameters such as Engine RPM, Engine temperature, Vehicle temperature, Throttle position, Vibration, Acceleration, Vehicle speed, Vehicle position, Displacement etc.

Synchronization between multiple DAQPORT boards can be achieved using dedicated on-board RF link. This DAQPORT board forms a critical subcomponent of the DAQPORT system along with the rugged LAPTOP (e.g. Panasonic – Toughbook notebook computer) and Wireless LAN adapters.

Two such DAQPORT systems are used outside the vehicle to acquire the audio data. In this case both the systems are configured as slave, receiving synchronization triggers from the Master system in the vehicle.

These systems are configured to acquire and store single channel audio data only. The vehicular system involves a few additional components such as Laser range finder, WAP wireless G Access point and additional external display to act as indicator for the Vehicle driver.

Laser based range finder is used for generating the position of vehicle with accuracy of 0.1 m with respect to a fixed reference point on the track. The data from the laser diode based range finder is acquired by DAQPORT board in the vehicular system. The technical comparison of the advanced Pass-by noise with commercial software is given in the below table:-

Sr. No. With the Advance Pass-by noise Software/Hardware System With the Conventional Commercial Software/Hardware

1. Data Acquisition system Multi channel high speed ADC (Engine RPM, Vibration, Acceleration) Multi channel ADC (Engine temperature, vehicle speed, vehicle position and displacement) Multiple Audio channels Data Acquisition system Multi channel high speed ADC (Engine RPM, Vibration, Acceleration) Multi channel ADC (Engine temperature, vehicle speed, vehicle position and displacement) Multiple Audio channels
2. Unit for vehicle laser based Bluetooth interface technology, wireless access point, wireless LAN adaptor, Master systems, Panasonic tough book, GPRS and signal transmitter
3. Unit on Ground wireless LAN adaptor, Slave systems and laser distance meter Unit on Ground Wireless LAN components, VME bus controller, IBM laptop
4. Compatible for ISO 362 measurements and upcoming new procedure Optimized for ISO 362 measurements
5. A substantially Low Cost system costing just about Rs. 35 Lakhs. An expensive system, costing about Rs. 1.5 cores.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The advanced pass-by noise system for an automobile in accordance with the present invention has the following advantages:

• The developed system can be used on any vehicle.

• Exact noise source can be predicted during the pass by noise test.

• Substantially lower cost, i.e. about 1/3rd of the conventional system.

• Laser-based technology, which is very cost effective and efficient.

• Well-tested on a vehicle model, whereby the noise source could be identified and suitably rectified to meet the pass by noise for the vehicle.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention.

Although, only the preferred embodiments have been described herein, the skilled person in the art would readily recognize to apply these embodiments with any modification possible within the spirit and scope of the present invention as described in this specification.

Therefore, innumerable changes, variations, modifications, alterations may be made and/or integrations in terms of materials and method used may be devised to configure, manufacture and assemble various constituents, components, subassemblies and assemblies according to their size, shapes, orientations and interrelationships.

The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.