Claims:CLAIMS:
What is claimed is:
1. A vacuum switch for detecting vacuum pressure, , the vacuum switch comprises:
a first housing comprising:
a face seal for preventing external leakage getting in to the vacuum switch and vice versa;
a first spring for measuring vacuum pressure; and
a spring holder for holding the first spring in place from the outer side;
a second housing comprising:
a diaphragm for sealing the vacuum switch;
a magnet, and wherein the said magnet is a temperature resistant, with very low temperature co-efficient ;
a magnet holder fixed concentrically on the other side of the diaphragm through a tab provided on the diaphragm, for carrying the magnet; and
a second spring for holding the said magnet holder attached to the diaphragm; and
a third housing comprising:
an O-ring for creating a sealing at the interface between the second housing and the third housing;
a printed circuit board (PCB) assembly is supported mechanically and wherein printed circuit board (PCB) assembly comprises one or more electronic components and an electrical interface for external connectivity;
a sensor for switching; and
an encapsulation, and wherein the PCB assembly and the sensor are encapsulated in the third housing for the protection from an external environment; and
wherein the diaphragm is a flexible seal which moves with respect to the vacuum pressure as per the first spring compression rate and along with that the diaphragm carries the magnet, and wherein the first spring is mechanically tuned to switch at a pre-set pressure band, and wherein when the first spring compresses at the required pressure value, the diaphragm will move along the gap provided in the first housing, and wherein the change in magnetic flux value is sensed by the sensor and the output voltage varies accordingly, and wherein the pressure is set to the desired switching pressure and the flux value is noted and the sensor is tuned for the switching at the said magnetic flux value, and wherein the change of switching state is programmed with defined hysteresis levels, and wherein once the sensor is tuned, the device starts switching at the set magnetic flux value which is correlated with pressure value.

2. The vacuum switch according to claim 1, wherein the clogging degree of the fuel filter is obtained from the vacuum switch and an alarm signal is generated as an output, when the clogging degree exceeds a threshold value.

3. The vacuum switch according to claim 1, wherein the vacuum switch is fastened with a thread provided on the front housing with a face seal to ensure external leak proof with application of the vacuum pressure.

4. The vacuum switch according to claim 1, wherein the diaphragm pushes the first spring upon application of the vacuum pressure, and wherein the second spring which is always under compression; gets released with the movement of the diaphragm and in turn the magnet holder moves back along with the magnet, and wherein the position of the magnet is changed from the sensor, and wherein the change of position is sensed by sensor and the output varies accordingly.

5. The vacuum switch according to claim 1, wherein the pressure is pre-set to the desired switching pressure and the flux value is noted and the sensor is tuned for the switching, and wherein the change of switching state is programmed with defined hysteresis levels, and wherein the device starts switching at the set magnetic flux value which is correlated with pressure values.

6. The vacuum switch according to claim 1, wherein the diaphragm isolates the media from the input orifice and the magnet side.

7. The vacuum switch according to claim 1, wherein the electronics comprising the sensor and the PCB assembly are encapsulated in the third housing.

8. The vacuum switch according to claim 1, wherein the sensor is a Hall Effect sensor, and wherein the Hall Effect sensor is a transducer that varies its output voltage in response to a magnetic field.

9. The vacuum switch according to claim 1, wherein the vacuum switch further comprises a air vent attached either to the PCB assembly or to the second housing, and wherein the said air vent is a air permeable, and wherein the air vent allows only air to pass through and block the liquid medium under normal atmospheric pressure, and wherein the said air vent balances the external and internal pressure of the vacuum switch

10. The vacuum switch according to claim 1, is adopted for detecting fuel filter clogging in internal combustion engine.

Date: 24-Oct-2017 Dr. Babitha Tharappan
Place: Bangalore Counsel for the Applicant
, Description:
FORM 2
The Patents Act 1970
(39 of 1970)
&
The Patent Rules 2003
COMPLETE SPECIFICATION
(See Section 10 and rule 13)

TITLE OF THE INVENTION:
DEVICE FOR DETECTING VACUUM PRESSURE

APPLICANT:
Rotary Electronics Private Limited
No. 18, 5th Cross, 4th Stage, Industrial Town,
Rajajinagar, Bangalore 560044,
Karnataka, India.

PREAMBLE OF THE DESCRIPTION:
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
A) TECHNICAL FIELD

[0001] The present invention generally relates to a field of pressure sensing devices and particularly relates to a device for detecting vacuum pressure. The present invention more particularly relates to a vacuum switch for detecting vacuum pressure precisely.

B) BACKGROUND OF THE INVENTION

[0002] The purpose of the fuel filter is to protect the injection system in internal combustion engine. Incidentally, fuel includes foreign matters, for example, water, dust, and solid undesirable materials such as rust. These foreign matters or impurities need to be removed or filtered. Fuel filters eliminate impurities present in the fuel.

[0003] Fuel filters need to be maintained at regular intervals. This is usually a case of simply disconnecting the filter from the fuel line and replacing it with a new one; although some specially designed filters can be cleaned and reused many times. If a filter is not replaced regularly it may become clogged with contaminants and cause a restriction in the fuel flow, causing an appreciable drop in engine performance as the engine struggles to draw enough fuel to continue running normally. Hence, there exists a need for a system and apparatus for detecting clogging of the fuel filter and time to replace the clogged fuel filer to ensure proper functioning of the internal combustion engine.

[0004] Various fuel filter clogging detection devices are proposed in the art, which are mainly mechanical in nature. In mechanical clogging detectors, upon detecting clogging in the fuel filter, the clogging detectors switches from one state to another pre-determined state and intimate the operator by an alarm or a hazardous light. Theses mechanical fuel filters clogging detectors are more prone to external tolerances; each component in the clogging detectors does not behave the same. There will be some compensation required. Further, the variation between the said mechanical clogging detectors can be upto 1 bar. Hence, in mechanical clogging detectors, switching will not be precise.

[0005] In view of the foregoing, there is a need to provide an efficient device for precisely detecting clogging of fuel filter in internal combustion engine. There is also a need to provide an electro-mechanical switch for precisely detecting and switching clogging of fuel filter in a diesel powered internal combustion engine. Further, there is also a need to provide a programmable vacuum switch for detecting clogging of fuel filter and alarming an operator of a vehicle.

[0006] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.

C) OBJECT OF THE INVENTION

[0007] The primary object of the present invention is to provide a vacuum switch for detecting vacuum pressure precisely.

[0008] Another object of the present invention is to provide a vacuum switch for detecting clogging of fuel filter in diesel powered internal combustion engine.

[0009] Yet another object of the present invention is to provide a vacuum switch for precisely detecting clogging of fuel filter and alarming the operator of the vehicle.

[0010] Yet another object of the present invention is to provide a programmable vacuum switch, wherein switching values are accurately set.

[0011] Yet another object of the present invention is to provide a vacuum switch with a programmable sensor, wherein mechanical errors are compensated by a programmable senor.

[0012] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

D) SUMMARY OF THE INVENTION

[0013] The various embodiments of the present invention provide a vacuum switch for detecting vacuum pressure precisely. Further, the present invention provide a vacuum switch for detecting clogging of fuel filter in diesel powered internal combustion engine. The vacuum switch comprises a first housing, a second housing and a third housing. The first housing of the vacuum switch comprises a face seal for preventing external leakage getting in to the vacuum switch and vice versa, a first spring for measuring vacuum pressure and a spring holder for holding the first spring in place from the outer side. The vacuum switch is fastened with a fastening means such as but not limited to a thread provided on the front housing with the face seal to ensure external leak proof with the application of vacuum pressure.

[0014] According to an embodiment of the present invention, the second housing of the vacuum switch comprises a diaphragm for sealing the vacuum switch, a temperature resistant magnet with very low temperature coefficient, a magnet holder for carrying the magnet which is fixed concentrically on the other side of the diaphragm through a tab provided on the diaphragm, and a second spring for holding the said magnet holder attached to the diaphragm.

[0015] According to an embodiment of the present invention, the third housing of the vacuum switch comprises an O-ring for creating a sealing at the interface between the second housing and the third housing, a printed circuit board (PCB) assembly which is supported mechanically and the said PCB assembly comprises one or more electronic components and an electrical interface for external connectivity, a sensor for switching and an encapsulation. The PCB assembly and the sensor are encapsulated in the third housing for the protection from an external environment.

[0016] According to an embodiment of the present invention, the diaphragm is a flexible seal which moves with respect to the vacuum pressure as per the first spring compression rate, and along with that the said diaphragm carries the magnet. The first spring is mechanically tuned to switch at a pre-set pressure band. The first spring compresses at the required pressure value, and the diaphragm moves along the gap provided in the first housing which in-turn changes the magnetic flux. Further, the change in magnetic flux is sensed by the said sensor the output voltage varies accordingly. The pressure is set to the desired switching pressure and the flux value is noted and the sensor is tuned for switching at the said pre-set magnetic flux value. The change of switching state is programmed with a defined hysteresis levels, and once the sensor is tuned, the device starts switching at the set magnetic flux value which is correlated with the pressure values.

[0017] According to an embodiment of the present invention, the clogging degree of the fuel filter is obtained through the vacuum switch and an alarm signal is generated as an output, when the clogging degree exceeds a threshold value.

[0018] According to an embodiment of the present invention, the diaphragm pushes the first spring upon the application of the vacuum pressure. The second spring which is always under compression, gets released with the movement of the diaphragm and in turn the magnet holder moves back along with the magnet. The position of the magnet is changed from the sensor, and the change of position is sensed by the sensor and the output of the vacuum switch varies accordingly.

[0019] According to an embodiment of the present invention, the pressure is pre-set to the desired switching pressure and the magnetic flux value is noted and the sensor is tuned for switching. The change of switching state is programmed with defined hysteresis levels, and the vacuum switch starts switching at the set magnetic flux value which is correlated with pressure values.

[0020] According to an embodiment of the present invention, the diaphragm isolates the media from the input orifice and the magnet side.

[0021] According to an embodiment of the present invention, the electronics comprising the sensor and the PCB assembly are encapsulated in the third housing.

[0022] According to an embodiment of the present invention, the sensor is a Hall Effect sensor. The Hall Effect sensor is a transducer that varies its output voltage in response to a magnetic field.

[0023] According to an embodiment of the present invention, the filter attached to the PCB assembly is an air permeable. The filter allows only air to pass through and block liquid medium under normal atmospheric pressure.

[0024] According to an embodiment of the present invention, the vacuum switch further comprises a air vent attached either to the PCB assembly or to the second housing. The said air vent is a air permeable, allowing only air to pass through and block the liquid medium under normal atmospheric pressure. The said air vent balances the external and internal pressure of the cacuum switch.

[0025] According to an embodiment of the present invention, the magnet moves within the second housing. Further, when the diaphragm moves to and fro, the magnet moves along with the diaphragm which goes through the second spring. With the differential pressure, the magnet movement change, so this will change the magnetic flux and the flux value is sensed by the sensor, which is housed on the PCB assembly.

[0026] According to an embodiment of the present invention, the said vacuum switch is adopted for detecting clogging of fuel filter in the internal combustion engine, by sensing the vacuum pressure of the fuel exiting from the fuel filter precisely.

[0027] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating the preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

E) BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:

[0029] FIG. 1 illustrates a block diagram of a system for detecting clogging of fuel filter in diesel powered internal combustion engine, according to an embodiment of the present invention.

[0030] FIG. 2 illustrates a side view of the vacuum switch for precisely detecting vacuum pressure, according to an embodiment of the present invention.

[0031] FIG. 3 illustrates a cross-sectioned view of the vacuum switch for precisely detecting vacuum pressure, according to an embodiment of the present invention.

[0032] FIG. 4 illustrates a front side view of the vacuum switch for precisely detecting vacuum pressure, according to an embodiment of the present invention.

[0033] FIG. 5 is an exploded view of the vacuum switch illustrating mechanical and electronic components adopted for precisely detecting vacuum pressure, according to an embodiment of the present invention.

[0034] Although the specific features of the present invention are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.

F) DETAILED DESCRIPTION OF THE INVENTION

[0035] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.

[0036] The various embodiments of the present invention provide a vacuum switch for detecting vacuum pressure precisely. Further, the present invention provide a vacuum switch for detecting clogging of fuel filter in diesel powered internal combustion engine. The vacuum switch comprises a first housing, a second housing and a third housing. The first housing of the vacuum switch comprises a face seal for preventing external leakage getting in to the vacuum switch and vice versa, a first spring for measuring vacuum pressure and a spring holder for holding the first spring in place from the outer side. The vacuum switch is fastened with a fastening means such as but not limited to a thread provided on the front housing with the face seal to ensure external leak proof with the application of vacuum pressure.

[0037] According to an embodiment of the present invention, the second housing of the vacuum switch comprises a diaphragm for sealing the vacuum switch, a temperature resistant magnet with very low temperature coefficient, a magnet holder for carrying the magnet which is fixed concentrically on the other side of the diaphragm through a tab provided on the diaphragm, and a second spring for holding the said magnet holder attached to the diaphragm. The position of the magnet is changed from the sensor upon application of the external pressure. The change of position is sensed by the sensor and the output varies accordingly. The sensor is of a programmable kind. The change of magnetic flux is sensed by the sensor and the output voltage varies accordingly. The pressure is set to the desired switching pressure and the flux value is noted and the sensor is tuned for the switching at the pre-set magnetic flux value. The change of switching state is programmed with defined hysteresis levels. Once the sensor is tuned, the device starts switching at the set magnetic flux value which is correlated with pressure values. Further, the diaphragm isolates the media from the input orifice and the magnet side. The electronics are encapsulated in a separate housing.

[0038] FIG. 1 illustrates a block diagram of a system for detecting clogging of fuel filter in diesel powered internal combustion engine, according to an embodiment of the present invention. The system comprises a diesel fuel filter 102 for filtering foreign matters or contaminants such as but not limited to water, dust, and solid undesirable materials like rust from the diesel fuel, an Electronic Control Unit (ECU) 103 for controlling a series of actuators on an internal combustion engine to ensure optimal engine performance and a vacuum switch 101 for precisely detecting clogging of fuel filter.

[0039] According to an embodiment of the present invention, the said diesel fuel filter 102 is fixed in a fuel line, for screening out dirt and rust particles from the fuel, normally made into cartridges containing a filter paper. The said diesel fuel filter 102 comprises a fuel inlet 104 for receiving fuel from a fuel tank and a fuel outlet 105 for dispensing filtered dust free fuel from the diesel fuel filter 102 to the fuel injection system of the internal combustion engine. The said vacuum switch 101 is fixed at the fuel outlet 105 of the diesel fuel filter 102 for measuring the vacuum condition of the vacuum switch 101 as shown in FIG. 1.

[0040] FIG. 2 illustrates a side view of the vacuum switch for precisely detecting vacuum pressure, according to an embodiment of the present invention. The said vacuum switch 101 comprises a first housing 201 including a plurality of mechanical components for measuring vacuum condition; a second housing 202 including a magnet for sensing vacuum condition; a third housing 203 including a sensor Integrated Circuit; and a PCB assembly for sensing magnetic flux. The said vacuum switch 101 further comprises a wiring harness 204 for transferring measured value; and a connector 205 for connecting the said vacuum switch 101 to the ECU 103.

[0041] FIG. 3 illustrates a cross-sectioned view of the vacuum switch for precisely detecting vacuum pressure, according to an embodiment of the present invention. The first housing 201 of the vacuum switch 101 comprises a face seal 302 for preventing external leakage or dust or liquids getting in to the vacuum switch and vice versa; a first spring 306 for measuring vacuum pressure; and a spring holder 303 for holding the first spring 306 in place from the outer side. Further, the second housing 202 of the vacuum switch 101 comprises a diaphragm 301 for sealing the system; a magnet holder 304 fixed concentrically on the other side of the diaphragm 301 through a tab provided on the diaphragm 301, for carrying a magnet 305, and wherein the said magnet 305 is a temperature resistant and very low temperature coefficient magnet; and a second spring 307 for holding the said magnet holder 304 attached to the diaphragm 301. Further, the third housing 203 of the vacuum switch 101 comprises an O-ring 308 for creating a sealing at the interface (between the second housing 202 and third housing 203); a printed circuit board (PCB) assembly 310, which is mechanically supported and the said PCB assembly comprises one or more electronic components and an electrical interface for external connectivity using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate; a sensor 311 for switching; and an encapsulation 309. The entire rear unit is housed in the third housing 203 and is encapsulated with the PCB assembly 310 for the protection from external environment.

[0042] According to an embodiment of the present invention, the diaphragm 301 is a flexible seal which moves with respect to the vacuum pressure as per the first spring 306 compression rate, and along with that the diaphragm 301 carries the magnet 305. The first spring 306 is mechanically tuned to switch at a pre-set pressure value, i.e. the required pressure values at which the switching has to happen is mechanically tuned in the first spring 306. Further, when the first spring 306 compresses at the required pressure value, the diaphragm will move along the gap provided in the first housing 201. Subsequently, the second spring 307 helps in countermovement of the magnet 305, i.e. the second spring 307 moves the magnet 305 in the opposite direction, which in-turn holds the magnet holder 304 attached to the diaphragm 301 always.

[0043] According to an embodiment of the present invention, when the diaphragm 301 moves to and fro, the magnet 305 also moves within the second housing 202. The magnet 305 moves along with the diaphragm 301 which goes through the second spring 307. Further, with the differential pressure, the magnet 305 movement changes, so this will change the magnetic flux and the flux value is sensed by the sensor 311, which is housed on the PCB assembly 310.

[0044] FIG. 4 illustrates a front side view of the vacuum switch for precisely detecting vacuum pressure, according to an embodiment of the present invention. The vacuum switch 101 comprises a fastening means such as but not limited to a thread provided on the first housing as shown in FIG. 4. The vacuum switch 101 is fastened with the thread provided on the front housing with a face seal to ensure external leak proof and vice versa with the application of vacuum pressure.

[0045] FIG. 5 is an exploded view of the vacuum switch illustrating mechanical and electronic components adopted for precisely detecting vacuum pressure, according to an embodiment of the present invention. The vacuum switch 101 comprises a face seal 302 for preventing external leakage and vice versa, a first spring 306 for measuring vacuum pressure; and a spring holder 303 for holding the first spring 306, which are housed inside the first housing 201; a diaphragm 301 for sealing the system, a magnet holder 304 for carrying a magnet 305, and a second spring 307 for holding the said magnet holder 304 attached to the diaphragm 301, which are housed inside the second housing 202; an O-ring 308 for creating a sealing at the interface, a printed circuit board (PCB) assembly 310 mechanically supported for electrically connecting electronic components, and an encapsulation 309. The entire rear unit is housed in the third housing 203 and is encapsulated with the PCB assembly 310 for the protection from external environment.

[0046] According to an embodiment of the present invention, the vacuum switch 101 further comprises an air vent 501 attached either to the PCB assembly or to the second housing. The said air vent 501 is an air permeable, allowing only air to pass through and blocking the liquid medium under normal atmospheric pressure. The said air vent 501 balances the external and internal pressure of the vacuum switch 101.

[0047] According to an embodiment of the present invention, the third housing 203 of the vacuum switch 101 further comprises a hole at the center for expelling air from the third housing 203. The air vent 501 covers the said hole in the third housing 203.

[0048] According to an embodiment of the present invention, the O-ring 308, also known as a packing, or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface between the second housing 202 and the third housing 203.

[0049] According to an embodiment of the present invention, the sensor 311 is a Hall Effect sensor, and wherein the Hall Effect sensor is a transducer that varies its output voltage in response to a magnetic field. The Hall Effect sensors are used for: such as but not limited to proximity switching, positioning, speed detection, and current sensing applications.

G) ADVANTAGES OF THE INVENTION

[0050] The various embodiments of the present invention provide a vacuum switch for precisely detecting vacuum pressure. The said vacuum switch is adopted for precisely detecting clogging of fuel filter in a diesel powered internal combustion engine. This will enhance the life of the diesel fuel filter. With increased life of diesel fuel filter, the end user has a lower maintenance cost.

[0051] The vacuum switch of the present invention protects the fuel injection pump from damage due to usage of clogged filters beyond life.

[0052] The vacuum switch of the present invention is of electrically programmable type, and flexible enough to adapt in different requirements/environments.

[0053] The vacuum switch of the present invention delivers very low hysteresis.

[0054] The vacuum switch of the present invention gives direct analog output.

[0055] The electronics of the said vacuum switch are totally isolated from the working media.

[0056] 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 understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.

[0057] Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.

[0058] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.