FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL
Specification
(See section 10 and rule 13)
FILTERS USED IN AN INTERNAL COMBUSTION ENGINES
FLEETGUARD FILTERS PVT. LTD.,
an Indian Company
of "Kirloskar House", 100, Anand Park, Aundh, Pune 411 008,
Maharahtra, India
THE FOLLOWING SPEC IFICATION DESCRIBES THE INVENTION.

FIELD OF INVENTION:
This invention relates to filters used in an internal combustion engines. In particular this invention relates to method and apparatus used to monitor various filters used in an internal combustion engines.
INTRODUCTION:
Air filters, fuel filters and oil filters are used in an internal combustion engine. An air filter is used to separate dust and particulate matter from the air and a fuel filter is used to remove foreign matter and sediments found in the fuel storage tank. If combustion air and fuel is not filtered the particulate matters admitted into the combustion chamber would seriously damage the engine cylinders, piston rings, valve seats and fuel injection systems.
Oil filters are used to clean the lubricating oil which is used to lubricate the mating and moving surfaces of the engine to reduce the friction and transfer the heat generated. Any contaminant or foreign particles in this medium will cause scoring on the cylinder walls and reduce the efficiency at which the burning process happens.
All modern internal combustion engines whether stationary or automotive are provided with separate filtration units for air, fuel and lubricating oils. A freshly installed filter has an optimum filtration area and causes negligible resistance to flow of air, fuel or lubricating oils. However due to use, depending on the amount of particulate matter load present in the filtered medium, the filtration area progressively gets chocked. This constriction


reduces the flow of the filtered medium through the filter and causes an increase in pressure on the inlet side of the filter. This difference of pressure between the inlet and outlet side of a filter is known as the pressure drop across the filter. As the flow rate reduces the engine performance will deteriorate rapidly and so the filter needs to be either cleaned or replaced.
In early days filter change interval was decided based on the number of hours of operation of engine, the distance run by a vehicle or just by visual observation of the filter for the extent of dust load.
Extensive laboratory experiments and field data reveals that engine will starve for sufficient clean air when pressure drop across the air filtration system will reach about 25-30 inches of water column. So it is recommended to change or clean the air filter when this level is reached. Like wise this recommendations are also formulated for fuel and oil filters either in terms of number of hours of operation as in the case of a stationary engine or distance covered in the case of an automotive engine. Almost all filters are designed as well as tested in laboratory for and up to this formulated pressure drop levels.
To overcome the hour, distance or experience based methodology for filter change interval a product for monitoring filter condition came in use in 80's. This product is used for air filtration system. This product is a small cylindrical transparent tube, in which a red plastic wedge is seated on the spring. As the pressure drop increases on the downstream of the air cleaner, vacuum will be created inside this tube, which will pull the red wedge downwards against the force of the spring. When the lower part of this


wedge crosses a certain mark, which is calibrated against the ultimate pressure drop, the filter is suppose to be changed or cleaned.
This type of filter monitoring unit is widely used in modern day air intake systems. Such units based on same working principle are also used in oil and fuel filter systems. As these involve costly instrumentation these products are used in very few systems where the filter change is very critical to the equipment performance and needs to be precise.
OBJECTS OF THE INVENTION:
One of the objects of this invention is to provide a filter monitoring unit suited to annunciate choking conditions of all the three filtration systems installed in an internal combustion engine like air, oil and fuel filters.
Yet another object of this invention is to provide a filter monitoring unit that uses very few sensors.
Yet another object of this invention is to provide a filter monitoring unit that is responsive to flow variations.
Yet another object of this invention is to provide a filter monitoring unit that is cost effective.
Yet another object of this invention is to provide a filter monitoring unit that is easy to install.


Yet another object of this invention is to provide a filter monitoring unit that is capable of raising visual and sound alarms.
Yet another object of this invention is to provide a filter monitoring unit that is capable of being mounted away from the engine room or compartment as the case may be.
SUMMARY OF THE INVENTION:
In accordance with this invention there is provided a filter monitor unit system and apparatus for monitoring and annunciating filter condition consisting of:
1) Mapping of load condition specific to engine model and dust environment and
2) Development of sensor less annunciation application based on operating history.
PHASE- I: MAPPING OF LOAD CONDITION SPECIFIC TO ENGINE MODEL AND DUST ENVIRONMENT:
In this phase a data acquisition system is prepared, having layout as follows. The air filter will be connected with absolute pressure sensor at the outlet of the air housing which will measure pressure drop across the air cleaner. Oil and fuel filter will be connected with upstream and downstream pressure gauges which will help to measure pressure drop across the filters. In addition to this pressure sensors there will be throttle position sensor, engine RPM sensor and vehicle speed (movement) sensor.


All these sensors will be connected to electronic consol of the filter monitor unit (FMU) which will house data logging hardware and will be powered by vehicle or engine battery. This FMU console will be interfaced with the software which will be configured with the ultimate pressure at which each of the filter type needed to be removed or cleaned.
During the operation of the vehicle or engine this unit will be automatically switched on and start logging real time values of the following parameters.
1) Pressure difference across the air cleaner.
2) Pressure difference across the fuel filter.
3) Pressure drop across the oil filter.
4) Engine RPM
5) Throttle position.
6) Vehicle speed. (If applicable).
The FMU unit will monitor these values and compare the same with the configured values for consistent output and indicate choking condition of that particular filter when the values exceed the configured values by a glowing LED light on the display panel.
There are LED displays on the unit to convey current condition of the filter in terms of CHOKED OR NON-CHOKED attribute values. Also this FMU
unit will also have facility to remove, clean or replace each filter individually with out affecting status of other filters.


At the end of the exercise, we will be having map which will tell us what is the operating condition of the vehicle or engine in terms of the load condition VS the engine RPM. The end map will look as shown in figure 2.
Filter usage map will have Engine RPM on the X axis and throttle position on Y axis. Maximum values of the both axis will be 100% of the engine rated conditions.
The total map will be divided in to different operating zones (81 zones at present). And software will display the particular operating zone with a color coding in which the filter is choked. These maps will be different for all three filters. This map will also acquire number of minutes for which the vehicle was running in that operating zone.
Each of these zones will be attributed with a certain pressure value at which software will indicate the choking condition of that particular filter in that particular zone.
For example in figure below all the zones in which engine is used is highlighted with the red color with number of minutes of operation at the centre and all the zones which are not used are highlighted with the green color showing "0" at the centre.
PHASE II: MAP BASED METHOD TO ANNUNCIATE FILTER CHOKING CONDITION:
In second phase of the product development data in the form of the map acquired for various applications for particular specifications of the engine


will be used to predict the filter choking condition for that particular combination of vehicle, engine and environment.
Map acquired through the phase one will be loaded in a memory card and from the time of installation of the new filter, system will start counting time spend in each of the operating section in decreasing order. The time spend by that combination in of engine in that cell of load condition will be reference for the counting.
Once all the cells of the map become zero (time spend by the vehicle in all the operating zones are repeated) filter monitoring unit will annunciate that filter as choked.
Here it is possible to change one type of filter without hampering downloaded data of the other filters. Also this system will use available sensors on the vehicle to acquire the operating load data.
BRIEF DESCRIPTION OF THE DRAWINGS:
This invention will now be described with reference to the accompanying drawing in which,
Figure 1 is the schematic diagram of the fuel monitor unit (FMU) in accordance to this invention, wherein the details of inter connection of the data acquiring methodology is depicted.
Figure 2 is the graphical representation of the acquired data of Phase I in accordance to this invention.


DETAILED DESCRIPTION OF THE DRAWING
Referring to Figure 1 the data acquisition system consists of an electronic console. The air filter will be connected with absolute pressure sensor at the outlet of the air housing which will measure pressure drop across the air cleaner. Oil and fuel filter will be connected with upstream and downstream pressure gauges which will help to measure pressure drop across the filters. In addition to this pressure sensors there will be throttle position sensor, engine RPM sensor and vehicle speed (movement) sensor.
All these sensors will be connected to electronic consol of the filter monitor unit (FMU) which will house data logging hardware and will be powered by vehicle or engine battery. This FMU console will be interfaced with the software which will be configured with the ultimate pressure at which each of the filter type needed to be removed or cleaned.
Figure 2 is the plot of the acquired data of phase I at different operating
condition of the vehicle or engine in terms of the load condition VS the
engine RPM.
Filter usage map will have Engine RPM on the X axis and throttle position
on Y axis. Maximum values of the both axis will be 100% of the engine
rated conditions.
The total map will be divided in to different operating zones (81 zones at
present). And software will display the particular operating zone with a
color coding in which the filter is choked. These maps will be different for
all three filters. This map will also acquire number of minutes for which the
vehicle was running in that operating zone.


While considerable emphasis has been placed herein on the particular features of "filter monitoring unit" and the improvisation with regards to it, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments 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.