Claims:We claim:

1. A vehicle occupant detection system (100), said system comprising:

(a) a plurality of occupant detection sensor (ODS) cells, each ODS cell includes a multi-layered structure and has a predetermined shape;

(b) said ODS cells placed on the vehicle seat/s in a predetermined configuration;

(c) said ODS cells connected to Engine Control Unit (ECU) of the vehicle engine; and

(d) said ECU connected to safety and/or auxiliary feature/s of said vehicle for timely deployment thereof;

wherein said system is configured to detect the presence of the vehicle occupant/s on vehicle seat/s based on the weight of said vehicle occupant/s sensed by said ODS cells as a function of the resistance change/s occurring in the circuit of said ODS cell/s detected by means of said ECU.

2. Vehicle occupant detection system (100) as claimed in claim 1, wherein said ODS cells are configured in a multi-layered structure having circuitry embedded in multiple layers of materials combined together as a sheet material integrated in a predefined pattern by means of adhesives to be placed on said vehicle seat/s.

3. Vehicle occupant detection system (100) as claimed in claim 2, wherein said integrated sheet material comprises resistive sheet made of one or more resistive material, conductive fabric, protective lamination sheet and adhesive layer each, and said resistive sheet is configured to function as a non-conductor of electricity or as a highly resistive material based on the weight of the occupant/s sensed by said ECU.
4. Vehicle occupant detection system (100) as claimed in claim 3, wherein said resistive sheet functions as a switch actuated by the changed cross-sectional area thereof to differentiate said vehicle occupant/s between adult vehicle occupant/s and child vehicle occupant/s seated on said vehicle seat/s.

5. Vehicle occupant detection system (100) as claimed in claim 3, wherein said resistive sheet functions as a switch actuated by the change in thickness of the dielectric fluid in said conductive fabric to differentiate said vehicle occupant/s between adult vehicle occupant/s and child vehicle occupant/s seated on said vehicle seat/s.

6. Vehicle occupant detection system (100) as claimed in claim 3, wherein the resistance change in said ODS cells occurs along and/or across said resistive sheet/s after said vehicle seat/s is occupied by said vehicle occupant/s.

7. Vehicle occupant detection system (100) as claimed in claim 3, wherein said ODS cell comprises a resistive sheet sandwiched between two conductive sheets of the same cross-section.

8. Vehicle occupant detection system (100) as claimed in claim 3, wherein said ODS cell comprises two conductive sheets of the same or different cross-sections placed over the same side of said resistive sheet and disposed along the surface thereof.

9. Vehicle occupant detection system (100) as claimed in claim 3, wherein said resistive sheet is square-shaped.

10. Vehicle occupant detection system (100) as claimed in claim 3, wherein said resistive sheet is circular.
11. Vehicle occupant detection system (100) as claimed in claim 3, wherein said ODS cell comprises a square cross-section.

12. Vehicle occupant detection system (100) as claimed in claim 1, wherein said ODS cell/s are connected together in a series matrix.

13. Vehicle occupant detection system (100) as claimed in claim 1, wherein said ODS cell/s are connected together in a cross-matrix.

14. Vehicle occupant detection system (100) as claimed in claim 12, wherein said series matrix comprises (2n+1) number of ODS cell/s.

15. Vehicle occupant detection system (100) as claimed in claim 14, wherein each ODS cell of said series matrix comprises a respective switch (Sw1, Sw2, ….. Swn) for switching-on or switching-off said ODS cell.

16. Vehicle occupant detection system (100) as claimed in claim 13, wherein said series matrix comprises (2n) number of ODS cell/s.

17. Vehicle occupant detection system (100) as claimed in claim 16, wherein each ODS cell of said cross-matrix comprises a respective switch (Sw1, Sw2, ….. Swn) for switching-on or switching-off said ODS cell.

18. Vehicle occupant detection system (100) as claimed in claim 1, wherein each of said ODS cell is connected to a voltage divider circuit with the input voltage (VIN) thereof applied to said circuit and output voltage (VOUT) thereof connected to said ECU.

19. Vehicle occupant detection system (100) as claimed in claim 3, wherein said resistive sheet comprises a circular cells connected together in a cross-matrix in an eight-layer structure.

20. Vehicle occupant detection system (100) as claimed in claim 3, wherein said resistive sheet comprises a square cells connected together in a series-matrix in an eight-layer structure.

21. Vehicle occupant detection system (100) as claimed in claim 19 or 20, wherein said eight-layer structure comprises:

(i) two outermost layers (L1, L8) forming a covering film;

(ii) two layers (L2, L7) disposed inside said outermost layers (L1, L8) forming an adhesive film;

(iii) a pair of middle layers (L3, L6) of conductive fabric;

(iv) a pressure sensitive conductive sheet (L4); and

(v) a layer (L5) of a non-conductive layer;

wherein said pressure sensitive conductive sheet (L4) has a variable resistance showing a change in resistance proportional to the pressure applied on said multi-layered ODS cell structure.

Dated this 05th day of March 2020.

Digitally Signed.

(SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT
REGN. NO. IN/PA-2043.

, Description:FIELD OF INVENTION

The present invention concerns a system for detecting occupant/s in a vehicle. In particular, the present invention concerns an intelligent system for assessing and counting the number of various occupant/s irrespective of the state of motion thereof. More particularly, the present invention concerns an improved configuration of the vehicle occupancy detection sensor fitted on vehicle seat.

BACKGROUND OF THE INVENTION

Conventionally, the vehicle occupant detection systems are used for different purposes in automotive applications in a variety of conditions during the day, night, inclement weather, glaring sunlight and even through highly tinted windshields.

This may be required for numerous automotive applications like, safety airbags or other pyrotechnically deployed restraints in the event of predetermined severity of a vehicle crash, to count the number of vehicle occupants to check violations of vehicle occupancy limits, to monitor the presence of unattended child left behind in an empty vehicle or to check the vehicle occupants location and/or position for the precise deployment of the climate control system therein.

One of the most important and utilized occupant detection and classification application is frequently used in connection with safety air bags and other pyrotechnically deployed restraints to determine as to whether and when such safety restraints should be actuated, if the vehicle crash is detected to be serious/severe enough for deployment for the safety of the vehicle occupants.

The presently available vehicle occupancy detection systems function as a switch and involve weight measurement based on the capacitance due to change in air gap. This weight measurement is also based on the number of sensors compressed by the vehicle occupant present on the vehicle seat.

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 improved vehicle occupant detection system.

Another object of the present invention is to provide an easy to install and manufacture vehicle occupant detection system.

Still another object of the present invention is to provide a resistance-based vehicle occupant detection system.

Yet another object of the present invention is to provide a low-cost vehicle occupant detection system.

A further object of the present invention is to provide an improved vehicle occupant detection system which facilitates safety-related decision-making.

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.

DESCRIPTION OF THE INVENTION

In accordance with the present invention, a vehicle occupant detection system consists of multiple sensors embedded in the vehicle seat/s. The sensors are configured with circuitry embedded in multiple layers of materials combined together as a sheet material in a predefined pattern by means of adhesives.

This sensor is fabricated based on the principle of resistance change occurring both across and along the resistive sheet and detects the vehicle occupants in all scenarios with optimum shape and materials used for fabrication of seats. This ODS sensor utilizes layers of Velostat (resistive material), conductive fabric, lamination layer and adhesives. Velostat is a polymeric foil (polyolefins) impregnated with carbon black to make it electrically conductive.

In no load condition, the configured foil/sheet material acts as a non-conductor of electricity or as a highly resistive material. The conductance increases across the foil with application of pressure perpendicular to surface of the foil.

This principle of Velostat is used to create a pressure sensitive variable resistance whose resistance change is proportional to pressure applied. Layers of conductive fabric is laminated on both sides of the switch to tap the resistance change.

These individual ODS sensors are combined in a predefined patterns to configure the ODS in accordance with the present invention. The signal from this ODS sensor can also be used in suspension tuning depending on the number of vehicle occupants and for powertrain tuning with respect to approximate occupants’ load.

In contrast to the currently available ODS sensor, which utilizes the principle of change in capacitance by a change in di-electric foam thickness between two conductive materials, the variable resistance principle used in this ODS configured in accordance with the present invention uses a unique combination of materials to achieve the desired results, which is useful and low-cost for occupant detection and characterization.

This unique combination of material primarily acts as a switch and uses cross-section area-based approach to characterize the vehicle occupants into adult and child occupant. Another embodiment of the present invention utilizes the change in dielectric fluid thickness to achieve the desired results.

This ODS sensor uses a protective lamination sheet to keep the material combination intact and safe from physical and environmental abuse.

Accordingly, the present invention utilizes different combinations of resistive membrane and conductive fabric protected with a lamination sheet. Table below describes the shape, order and related details for different combinations of resistive sheet and conductive fabric used for this ODS sensor:

Combination No. Type Shape of Sensor Order Direction
1 Single Square CVC Across
2 Matrix Circular CVC Across
3 Single Square CCV Along
4 Single Circular CCV Along
5 Matrix Square CCV Along

C-Conductive Fabric, V-Velostat

The ODS sensor fabricated according to the present invention uses the principle of change in resistance, both across and along the resistive sheet. The basic configuration of ODS sensor consists of at least one resistive sheet sandwiched between two conductive sheets with same cross-section area and is generally square in shape, however not limited to this shape. The electric current flows across the resistive sheet and is sensitive to the force and pressure applied thereon vertically.

The second embodiment of ODS sensor consists of two different sections of conductive fabric placed over the same side of the resistive sheet, i.e. along the surface. Here, two different comb-like sections of conductive fabric are combined to form a square surface with no contact interference between these sections. Here, the principle of sheet resistance is used, and the resistive sheet has a square cross-section with conductive sheets placed on the same side.

These two basic configurations are arranged in the form of a matrix with different connection pattern to configure the Occupancy Detection Sensor.

Accordingly, when force/pressure is applied across or along the pressure sensitive resistive sheet, the resistance varies and used to detect the presence of load/measure load etc. However, the ODS sensor can be made of any number of layers, with the only difference in the change in resistance values.

SUMMARY OF INVENTION

In accordance with the present invention, there is provided a vehicle occupant detection system, the system comprising:

• a plurality of occupant detection sensor (ODS) cells, each ODS cell includes a multi-layered structure and has a predetermined shape;

• the ODS cells placed on the vehicle seat/s in a predetermined configuration;

• the ODS cells connected to Engine Control Unit (ECU) of the vehicle engine; and

• the ECU connected to safety and/or auxiliary feature/s of the vehicle for timely deployment thereof;

wherein the system is configured to detect the presence of the vehicle occupant/s on vehicle seat/s based on the weight of the vehicle occupant/s sensed by the ODS cells as a function of the resistance change/s occurring in the circuit of the ODS cell/s detected by means of the ECU.

Typically, the ODS cells are configured in a multi-layered structure having circuitry embedded in multiple layers of materials combined together as a sheet material integrated in a predefined pattern by means of adhesives to be placed on the vehicle seat/s.

Typically, the integrated sheet material comprises resistive sheet made of one or more resistive material, conductive fabric, protective lamination sheet and adhesive layer each, and the resistive sheet is configured to function as a non-conductor of electricity or as a highly resistive material based on the weight of the occupant/s sensed by the ECU.

Typically, the resistive sheet functions as a switch actuated by the changed cross-sectional area thereof to differentiate the vehicle occupant/s between adult vehicle occupant/s and child vehicle occupant/s seated on the vehicle seat/s.

Typically, the resistive sheet functions as a switch actuated by the change in thickness of the dielectric fluid in the conductive fabric to differentiate the vehicle occupant/s between adult vehicle occupant/s and child vehicle occupant/s seated on the vehicle seat/s.

Typically, the resistance change in the ODS cells occurs along and/or across the resistive sheet/s after the vehicle seat/s is occupied by the vehicle occupant/s.

Typically, the ODS cell comprises a resistive sheet sandwiched between two conductive sheets of the same cross-section.

Typically, the ODS cell comprises two conductive sheets of the same or different cross-sections placed over the same side of the resistive sheet and disposed along the surface thereof.

Typically, the resistive sheet is square-shaped.

Typically, the resistive sheet is circular.

Typically, the ODS cell comprises a square cross-section.

Typically, the ODS cell/s are connected together in a series matrix.

Typically, the ODS cell/s are connected together in a cross-matrix.

Typically, the series matrix comprises (2n+1) number of ODS cell/s.

Typically, each ODS cell of the series matrix comprises a respective switch (Sw1, Sw2, ….. Swn) for switching-on or switching-off the ODS cell.

Typically, the series matrix comprises (2n) number of ODS cell/s.
Typically, each ODS cell of the cross-matrix comprises a respective switch (Sw1, Sw2, ….. Swn) for switching-on or switching-off the ODS cell.

Typically, each of the ODS cell is connected to a voltage divider circuit with the input voltage (VIN) thereof applied to the circuit and output voltage (VOUT) thereof connected to the ECU.

Typically, the resistive sheet comprises a circular cells connected together in a cross-matrix in an eight-layer structure.

Typically, the resistive sheet comprises a square cells connected together in a series-matrix in an eight-layer structure.

In an embodiment of the present invention, the eight-layer structure comprises:

- two outermost layers forming a covering film;

- two layers disposed inside the outermost layers forming an adhesive film;

- a pair of middle layers of conductive fabric;

- a pressure sensitive conductive sheet; and

- a layer (of a non-conductive layer;

wherein the pressure sensitive conductive sheet has a variable resistance showing a change in resistance proportional to the pressure applied on the multi-layered ODS cell structure.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described in the following with reference to the accompanying drawings.
Figure 1a shows a detailed view of a typical sensor for conventional vehicle occupant detection system (ODS).

Figure 1b shows the cross-sectional view of Sensor 1 across section line A-A marked in Figure 1a.

Figure 1c shows an exploded view of the components of the membrane of sensor of Figure 1a.

Figure 1d shows the schematic circuit diagram of sensor 1 of Figure 1a.

Figure 2a shows the ODS sensor configured in according to the invention.

Figure 2b shows the ODS sensor of Figure 5a, connected to a voltage divider circuit and power supply.

Figure 3 shows the flow diagram of operation of the vehicle occupant detection system configured in accordance with the present invention.

Figure 4a shows a schematic cross-sectional view of the occupancy detection sensor of Fig.1 configured in accordance with the present invention.

Figure 4b shows a perspective view of a multilayered configuration of the first embodiment of the sensor of the present invention.

Figure 4c shows a typical vehicle seat with sensors placed thereon and connected to the engine ECU by wires.

Figure 5a shows an unloaded state of ODS sensor of Figure 5a placed on a vehicle seat and an enlarged view thereof.

Figure 5b shows a loaded state of ODS sensor of Figure 2a once a vehicle occupant is seated on seat fitted with ODS sensor system and applies pressure on the pressure sensitive sheet.

Figure 5c(i) shows a first exemplary circular cell configured in accordance with the present invention.

Figure 5c(ii) shows a first exemplary matrix of ODS sensor made with four circular cells, each disposed at the flange end thereof.

Figure 5d(i) shows a second exemplary square cell configured in accordance with the present invention.

Figure 5d(ii) shows a second exemplary matrix of ODS sensor made with four square cells, each disposed at the flange end thereof.

Figure 6a shows a first embodiment of the sensor cell shown in Figure 4a.

Figure 6b shows a second embodiment of the sensor cell shown in Figure 4a.

Figure 6c shows a third embodiment of the sensor cell of Fig. 4a, both in plan (i) and side view (ii) thereof.

Figure 6d shows a fourth embodiment of the sensor cell of Fig. 4a, both in plan (i) and side view (ii) thereof.

Figure 7a shows a cell design for resistance change across Velostat.

Figure 7b shows an optional cell design for resistance change across Velostat using two sheets of Velostat sandwiched between layers of conductive fabric.

Figure 8 shows an exploded view of the circular cross-matrix sensor used for lab-testing.

Figure 9a shows the change in resistance along the Velostat.

Figure 9b shows a perspective view (i) and a side view (ii) indicating the change in resistance across the Velostat.

Figure 10a shows an embodiment of ODS sensor 116 shaped in a series matrix of square-shaped cells.

Figure 10b shows an embodiment of the ODS sensor shaped in a cross- matrix of circular-shaped cells.

Figure 11a shows a typical circuit diagram of an embodiment of the ODS sensor with a series matrix of square-shaped cells as shown in Figure 10a.

Figure 11b shows a typical circuit diagram of an embodiment of the ODS sensor shaped in a cross- matrix of circular cells as shown in Figure 10b.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following the vehicle occupant detection system 100 configured in accordance with 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.

Figure 1a shows a detailed view of sensor 1 having a double-T profile with four sensor cells 2, each being disposed at four flange ends (I, II, III, IV) and an adapter 3 disposed at the web end of the membrane 4 thereof. Section line A-A is also marked to describe below the construction of this sensor 1.

Figure 1b shows the cross-sectional view of Sensor 1 across the section line A-A marked in Figure 1a. Sensor 1 includes a dual-electrode (8a, 8b) disposed between an upper PET film 51 and a lower PET film 52. The upper and lower films 51, 52 are spaced apart by a predefined distance by pasting a PET spacer 6 therebetween by means of adhesive material 7a. The dual electrode includes inner carbon electrodes 8a and respective silver electrodes 8b adjacent the inner faces of upper and lower PET films 51, 52. A release paper 9 is also pasted on the lower face of the lower PET film 52 by means of adhesive material 7b for assembly of the sensor 1 on the vehicle seat. Typical thickness of upper and lower PET films 51, 52 and PET spacer 6 is about 100 µm. Further, the distance between upper and lower PET films 51, 52 and adhesive material 7b used for pasting of release paper 9 (thickness ~ 100 µm) is about 150 µm each.

Figure 1c shows an exploded view of the components of membrane 4 of sensor 1 of Figure 1a. Membrane 4 includes upper PET film 51 and lower PET film 52 separated by spacer 6 and pasted with adhesive 7b for pasting of release paper 9 (Figure 1b) on the lower face of lower film 52.

Figure 1d shows a schematic circuit diagram of sensor 1 of Figure 1a. It includes switches Sw1, Sw2, Sw3, Sw4 for respective sensor cells 2 disposed at four flange ends I, II, III, IV thereof. The circuit has a rated voltage of 12V, working voltage of 0~19V and maximum current 15mA at operating temperatures between - 40oC and 85oC. Here, the ODS circuit remains switched off until the resistance detected by sensor 1 is more than 1M? and ODS 100 is switched on as soon as the resistance detected by the sensor 1 falls below 400?.

Figure 2a shows the ODS sensor 100 configured in accordance with the present invention.

Figure 2b shows the ODS sensor of Figure 2a, connected to a voltage divider circuit and power supply thereto. Here, the battery voltage VIN is the input voltage applied to one terminal of the circuit and VOUT is the output of the ODS sensor supplied to ECU. The value of constant resistance R is selected to condition the output of the sensor based upon different use case. The output voltage potential is across the constant resistance R.

Figure 3 shows the flow diagram of operation of the vehicle occupant detection system 100 configured in accordance with the present invention. It comprises a vehicle occupant 12 seated on a seat 14 fitted with an occupant detection sensor 16 therein. An electrical signal S1 is generated when an occupant occupies a seat 14 in the vehicle 20, which is passed on to the engine (Electronic Control Unit) ECU 18. Subsequently, depending on the change in resistance value detected by ECU 18, another signal S2 is passed on to raise an alarm 22 for reminding the seat occupant to use the safety seat belt and to safety air nag system to adjust the pressure therein according to the weight of the seat occupant (e.g. an adult of or a child) for subsequent deployment of the safety air bad system in case of any possible vehicle crash. Once vehicle occupant 12 is buckled to the seat belt of seat 14, ODS system 100 detects this seat buckling and is ready to issue another signal S3 for the deployment 24 of the safety airbag in the event of any possible vehicle crash.

Figure 4a shows a schematic cross-sectional view of the occupancy detection sensor 16 of Figure 3. In the most basic configuration (first embodiment) thereof, Sensor 16 includes a resistive material 162, e.g. Velostat sandwiched between conductive fabric sheets 164 disposed on either face thereof. Subsequently, a protective lamination sheet 166 each is pasted outside the conductive fabric sheets 164 on either thereof in a predefined pattern by means of adhesive 168 to keep sensor 16 intact and safe from physical and environmental degradation thereof.

Figure 4b shows a perspective view of a schematic arrangement of a resistive material (Velostat) sheet 162 sandwiched between two layers of e-textile (e.g. conductive fabric sheets and threads) 164 to make a multilayered configuration of the first embodiment of the sensor 16 of the present invention. It is to be noted that Velostat is a flexible, conductive material functioning as a variable resistor, the resistance thereof decreasing on compression or bending thereof. This multilayered configuration of ODS sensor 16 forms the crux of the pressure based vehicle occupancy detection of the present invention, which uses the aforementioned combination of materials. Sensor 16 is low-cost, highly flexible and easy to be integrated into vehicle seat 14.

Figure 4c shows a typical vehicle seat with a series of individual sensors 16 placed thereon and connected to the engine ECU 18 by means of wires 15 making a series of cross-matrix. Sensors 16 avoid any false true condition thereof.

Figure 5a shows an unloaded state of ODS sensor of Fig. 4a placed on seat 114 and covered by seat cover 115. ODS sensor 116 is configured with a seat belt reminder system (SBRS) 120 embedded therein, fitted within vehicle seat 114. The figure also shows an enlarged view of vehicle seat (encircled portion) with SBRS 120 therebelow, in an unloaded state.

Figure 5b shows the loaded state of ODS sensor 116 of Figure 5a, when a vehicle occupant 112 gets seated on vehicle seat 114, and the force/pressure is applied in the downward direction of load L on the pressure sensitive sheet SBRS 120 due to the seat occupant’s weight. This load L causes the resistance of the circuit (embedded in SBRS 120) to vary and to generate electrical signals in terms of a resistance change, which is used as an indicator of the presence of a seat occupant seated on vehicle seat 114. Although, only two-layered SBRS 120 is used here, this resistance change principle is applicable to any number of layers and the resistance change can be detected both across and along the direction of the load applied on vehicle seat 114 for different applications of this principle.

Figure 5c(i) shows an exemplary circular cell 216 configured in accordance with the present invention.

Figure 5c(ii) shows an exemplary matrix 200 of ODS sensor 100 made with four circular cells 216, each disposed at the flange end thereof.

Figure 5d(i) shows an exemplary square cell 316 configured in accordance with the present invention.

Figure 5d(ii) shows an exemplary matrix 300 of ODS sensor 100 made with four square cells 316, each disposed at the flange end thereof.

Figure 6a shows a first embodiment of the sensor cell 16 shown in Figure 4a. It comprises a typical combination in which electric current flows along resistive sheet 162 from one conductive fabric shape 164 to another. The force applied perpendicular to these resistive sheets reduces the sheet resistance thereof and thereby reduces the overall resistance across sensor cell 16. The resistance change of single cell 16 depends on the shape thereof, especially on the shape of resistive material thereof.

Figure 6b shows a second embodiment of the sensor cell 16 shown in the Figure 4a. It comprises a typical combination in which electric current flows across two resistive sheets 162 from one conductive fabric sheet 164 to another. The force applied perpendicular to resistive sheets 162 reduces the sheet resistance thereof and reduces the overall resistance across sensor cell 16. This single cell 16 can be configured square or circular (Figures 9a, 10a).

Figure 6c shows a third embodiment of the sensor cell 16 shown in Fig. 4a, depicting both plan (i) and side view (ii) thereof. Here, sensor cell 16 comprises a typical combination in which electric current flows along a resistive sheet 162 from one conductive fabric sheet 164 to another. The force applied perpendicular to resistive sheet 162 reduces the sheet resistance thereof and overall resistance decreases across two conductive sheets 164.

Figure 6d shows a fourth embodiment of the sensor cell 16 shown in Fig. 4a, depicting both plan (i) and side view (ii) thereof. Here also, sensor cell 16 comprises a typical combination in which electric current flows along two resistive sheet 162 from one conductive fabric sheet 164 to another. The force applied perpendicular to resistive sheets 162 reduces the sheet resistance thereof and the overall resistance decreases across the sensor cell 16. The resistance change of single cell 16 depends the shape thereof, especially the shape of the resistive material.

Although, the vehicle occupant detection system (ODS) in accordance with the present invention is configured is different embodiments discussed above, however it is not limited to the ones disclosed herein.

Any sensor cell shape following the embodiments discussed above can be fabricated with minor changes in the resistance values.

Basic shapes like circular and square sensor cells discussed above were tried and tested. However, these basic sensor cells were also combined in predefined matrices, e.g. to form a corresponding four cell matrix discussed further below.

Figure 7a shows a cell design for resistance change across Velostat, in which a Velostat layer 162 is sandwiched between two conductive fabric layers 164.

Figure 7b shows an optional cell design for resistance change across Velostat using two sheets of Velostat sandwiched between layers of conductive fabric. Here, two Velostat layers 162 disposed adjacent to each other are sandwiched by a respective conductive fabric layer 164 disposed on the outer face thereof.

Figure 8 shows an exploded view of the circular cross-matrix sensor used for lab-testing, which is made of 8 layers (L1, L2, L3, L4, L5, L6, L7, L8) in all. Here, outermost layers L1 and L8 form a covering film (thickness < 150 µm). The layers L2, L7 disposed inside these outermost layers L1, L8 form an adhesive film (thickness ~ 100 µm). The middle layers L3, L6 are made of conductive fabric (80 µm thickness). There is also a pressure sensitive conductive sheet L4 (100 µm thickness). Finally, layer L5 is used to avoid interreference of conductive sheets, which is made of a non-conductive layer (thickness ~ 100 µm).

Figure 9a shows the change in resistance along the Velostat. Here, ODS sensor 116 is configured with two conductive fabric layers 164 placed on a Velostat layer 162 separated by a predefined distance to induce a change in the resistance along Velostat 162 in the direction of arrow shown in figure, which is captured as electrical signals generated and used to indicate the presence of an occupant sitting on the vehicle seat 114 (Figure 5b).

Figure 9b shows a perspective view (i) and a side view (ii) indicating the change in resistance across Velostat 162, i.e. through thickness of Velostat. Here, ODS sensor 116 includes two conductive fabric layers 164 placed on either face of a Velostat layer 162 and thus induces a change in the resistance (??R) perpendicular to the plane of figure, i.e. through thickness of Velostat.

Figure 10a shows an embodiment of ODS sensor 116 shaped in a series matrix of square-shaped cells, e.g. provided with 7 switches in Figure 11a.

Figure 10b shows an embodiment of the ODS sensor shaped in a cross- matrix of circular-shaped cells, e.g. provided with 4 switches in Figure 11b.

Figure 11a shows a typical circuit diagram of an embodiment of ODS sensor 116 with a series matrix of square-shaped cells and provided with 7 switches (Sw1, Sw2, Sw3 on one side, Sw4 in the middle, and Sw5, Sw6, Sw7 on the other side) in a series connection.

Figure 11b shows a typical circuit diagram of an embodiment of the ODS sensor with a cross- matrix of circular-shaped cells and provided with four switches (series connected pairs of Sw1, Sw2 and Sw3, Sw4 and connected to each other in series) in parallel connection.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The vehicle occupant detection system (ODS) configured in accordance with the present invention offers the following advantages:

• ODS detects vehicle occupant/s in all scenarios by optimum shape and materials used therefor.

• ODS sensor utilizes multiple layers materials and adhesives according to the vehicle safety requirement.

• Takes the shape of set form and finish by the threads and Velostat, a conductive, flexible material used here.

• ODS sensor signal also usable in suspension tuning based upon number of occupants.

• ODS sensor signal also usable in powertrain tuning with respect to approximate occupant load.

• ODS sensor facilitates in localization of HVAC settings to improve the efficiency thereof.

• ODS sensor uses protective lamination sheet to keep it intact and safe from physical and environmental abuse.

• ODS sensor system offers a low-cost, highly flexible sensor.

• ODS sensor system is easily integrated in the vehicle seat.

• Switch-based film, light-weight and thin sensor does not affect seating comfort.

• Vehicle occupant detection possible from low to high temperature.

• ODS sensor system improves vehicle occupant data collection to enhance decision making in the area of safety features, such as airbag deployment and seat-belt warning system for vehicles.

• ODS sensor system can be easily adopted to the vehicle seat layout.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

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. 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, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to imply 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 description of the exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top”, and “bottom” as well as derivatives thereof (e.g. “horizontally”, “inwardly”, “outwardly”; “downwardly”, “upwardly” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion.

These relative terms are for convenience of description and do not require that the corresponding apparatus or device be constructed or operated in a particular orientation. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected”, refer to a relationship, wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.