Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
[0001] The present disclosure relates a controller and method to detect absence of filter in an Exhaust Gas Treatment (EGT) system of a vehicle.

Background of the invention:
[0002] Detecting the missing filter in Exhaust gas Treatment System such as DNOX system at the earliest help to fix it as well to avoid blocking of injector of a dosing module due to filter missing between suction and pressure line. Basically, a missing filter leads to system performance related failures and component damage.

[0003] According to a prior art 201841027907 discloses a filtration apparatus for a diesel exhaust fluid (DEF) in an exhaust after-treatment system. The various embodiment of the present invention provides a filtration apparatus for DEF in an exhaust after-treatment system. The filtration apparatus comprises at least two filters, a first filter and a second filter, arranged in parallel between a supply end and a delivery end. In one embodiment, the supply end is a tank or a reservoir storing the DEF fluid and the delivery end is a supply module comprising at least one pump. Alternatively, the supply end is the supply module comprising the at least one pump and the delivery end is a dosing injector/module. The filtration apparatus improves the life time of the replaceable filters to an extent of approximately twice as in the existing filters. The flow from the supply end is directed through one filter at a time using controllable valves.

Brief description of the accompanying drawings:
[0004] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0005] Fig. 1 illustrates a block diagram of Exhaust Gas Treatment (EGT) system and a controller to detect absence of filter in a vehicle, according to an embodiment of the present invention;
[0006] Fig. 2 illustrates plots of signals from a pressure sensor with and without filter in the EGT system, according to an embodiment of the present invention, and
[0007] Fig. 3 illustrates a method for detecting absence of filter in the EGT system of the vehicle, according to the present invention.

Detailed description of the embodiments:
[0008] Fig. 1 illustrates a block diagram of Exhaust Gas Treatment (EGT) system and a controller to detect absence of filter in a vehicle, according to an embodiment of the present invention. The EGT system 100 comprises a tank 102 storing Diesel Exhaust Fluid (DEF), a supply module 104 to pump the DEF from the tank 102 to a dosing module 108 with a filter 106 therebetween, at least two conduits, namely, a delivery conduit 112 and a backflow conduit 114, fluidly connects the filter 106 to the dosing module 108 and the tank 102, respectively, a pressure sensor 116 to measure system pressure, and the controller 110 connected to the pressure sensor 116 and configured to activate the supply module 104 to pump DEF to dosing module 108, characterized in that, detect absent/missing filter 106 based on at least one parameter derived from signal read by the pressure sensor 116 while the DEF is being pumped by the supply module 104. The missing filter 106 is provided as output 120 through a display screen or audio signal or light or the like. The dosing module 108 contains injector which projects inside an exhaust conduit 118 of the vehicle.

[0009] According to an embodiment of the present invention, the parameter is at least one selected from a group comprising an amplitude of pressure pulses, a count of amplitude, and a time for pressure increase from x value to y value. The controller 110 configured to perform comparison of the derived parameter with respective threshold value. Specifically, a threshold amplitude is considered for the amplitude of each pressure pulses for comparison, a threshold count is considered for the count of amplitude for comparison, and a threshold time is considered for the time for pressure increase from x value to y value for comparison.

[0010] In accordance to an embodiment of the present invention, the pressure sensor 116 is connected to the backflow conduit 114 of the filter 106. Specifically, the pressure sensor 116 is connected to the backflow outlet port provided on a cover of the filter 106. The filter 106 is positioned inside a housing with the cover.

[0011] According to an embodiment of the present invention, the controller 110 is any one of a control unit internal to said vehicle and external to said vehicle. The internal control unit is any one of an Engine Control Unit and an Exhaust Control Unit, and the external control unit is a server, a cloud or a diagnostic device connected through any one of a wired and wireless means. The wired means comprises the Universal Serial Bus (USB) cable based connected to On-Board Diagnostic (OBD) port or Bluetooth dongle based connected to OBD, or the like.

[0012] In accordance to an embodiment of the present invention, the controller 110 is provided with necessary signal detection, acquisition, and processing circuits. The controller 110 is the control unit which comprises input/output interfaces having pins or ports, the memory element such as Random Access Memory (RAM) and/or Read Only Memory (ROM), Analog-to-Digital Converter (ADC) and a Digital-to-Analog Convertor (DAC), clocks, timers, counters and at least one processor (capable of implementing machine learning) connected with each other and to other components through communication bus channels. The memory element is pre-stored with logics or instructions or programs or applications or modules/models and/or threshold/ values/ranges/amplitude/counts/time, predefined/predetermined criteria, correction factor based maps/table which is/are accessed by the at least one processor as per the defined routines. The internal components of the controller 110 are not explained for being state of the art, and the same must not be understood in a limiting manner. The controller 110 may also comprise communication units to communicate through wireless or wired means such as Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks, and the like. The controller 110 is implementable in the form of System-in-Package (SiP) or System-on-Chip (SOC) or any other known types. Examples of controller 110 comprises but not limited to, microcontroller, microprocessor, microcomputer, etc.

[0013] Fig. 2 illustrates plots of signals from a pressure sensor with and without filter in the EGT system, according to an embodiment of the present invention. A graph 200 is shown with two plots, a first plot 206 represents a pressure curve with filter 106, and a second plot 208 represents a pressure curve without filter 106 in the EGT system 100. The plots are shown in the graph 200 with X-axis 202 in time and Y-axis 204 in pressure with respective suitable units.

[0014] The first plot 206 is due to the air/gas which gets trapped in the cover of the filter 106 between the backflow port in the cover and the filter 106 and remain for few hours before escaping into the backflow/pressure conduit 114. This air acts as a natural dampener against pressure increase/decrease synchronized with the movements of a pump’s diaphragm. This results in a slow and steady pressure rise and minimal oscillations with respect to the system pressure measured from the pressure sensor 116 in the backflow line during pressure preparation.

[0015] The second plot 208 is when, air enters towards main filter area and escapes easily towards backflow/pressure line from the filter 106 as soon as the pump starts to pressurize the system 100, due to the lack of air and its dampening effect on the system pressure. Consequently, the pressure rises faster during pressure preparation, but also oscillates more in relation to the system pressure measured by the pressure sensor 116 which is mounted in the backflow port. In other words if the filter 106 is missing, air move out through backflow conduit 114 and delivery conduit 112 and eventually air is not trapped and compressed for dampening. This will result in considerable and consistent pressure pulsations 210. Due to the pressure pulsations 210, parameters are derived and compared with threshold values to detect absence of the filter 106. The parameters considered are but not limited to amplitude of system pressure oscillation threshold. (in Hpa and threshold is calibratable) and time taken for reaching pressure from point x → y (in milliseconds and duration is calibratable).

[0016] According to an embodiment of the present invention, the vehicle is which makes use of EGT system 100 such as cars, buses, Off-Highway Vehicles (OHW) and the like.

[0017] According to the present invention, a working of the controller 110 in the EGT system 100 is envisaged. Consider the vehicle fit with the EGT system 100 is in a service station for servicing. A service engineer services the vehicle and also the EGT system 100 by removing the filter 106. Assuming that the before assembling the EGT system 100 back, the filter 106 was missed to be placed. The service engineer performs the diagnostic using a tool connected to OBD port of the vehicle. While the diagnostic is performed, the controller 110 operates the supply module 104 and measures the pressure through the pressure sensor 116. The parameters are derived and compared with respective threshold and accordingly decides that the filter 106 is missing. The service engineer than puts the filter 106 back and prevents any possible malfunction or failure of the EGT system 100 by running without filter 106. This is an example and the same is possible to be checked in the vehicle directly or through remote location.

[0018] Fig. 3 illustrates a method for detecting absence of filter in the EGT system of the vehicle, according to the present invention. The EGT system 100 comprises the tank 102 storing the Diesel Exhaust Fluid (DEF), the supply module 104 to pump the DEF from the tank 102 to the dosing module 108 through the filter 106, at least two conduits, namely, the delivery conduit 112 and the backflow conduit 114, fluidly connects the filter 106 to the dosing module 108 and the tank 102, respectively, and the pressure sensor 116 to measure the system pressure. The method comprises plurality of the steps of which a step 302 which comprises activating the supply module 104 to pump DEF from the tank 102 to the dosing module 108. The method is characterized by a step 304 comprising detecting absent/missing filter 106 based on at least one parameter derived from signal read by the pressure sensor 116 while pumping the DEF.

[0019] According to the present invention, the parameter is at least one selected from the group comprising the amplitude of each pressure pulses, the count of amplitude of the pressure pulses, and time for pressure increase from x value to y value. The step 304 comprises comparing the parameter with respective threshold value, wherein the amplitude of each pressure pulse is compared with the threshold amplitude, the count of amplitude is compared with the threshold count, and the time for increase of pressure from x value to y value is compared against the threshold time.

[0020] According to the method, the pressure sensor 116 is connected to the backflow conduit 114. Specifically, the pressure sensor 116 is connected to the backflow port in the cover of the filter 106.

[0021] According to the present invention, the method is performed by the controller 110 which is any one of the control unit internal to the vehicle and external to the vehicle. The internal control unit is any one of the Engine Control Unit and the Exhaust Control Unit. The external control unit is the server, the cloud or the diagnostic device connected through any one of the wired and wireless means.

[0022] According to an embodiment of the present invention, a detection of missing filter 106 during early phase of EGT system 100 preparedness is provided. The present invention enables detection of the possible tampering by not assembling / removing the filter 106. The controller 110 and method enables detection of the missing filter 106 at the earliest and helps to fix it as well to avoid blocking of injector of dosing module 108 due to filter 106 missing between suction and pressure line. The present invention benefits the customers at their service station to realize the missing filter 106 of the EGT system 100 post servicing. The functionality detects the missing filter 106 during both normal and tester service routines.

[0023] According to an embodiment of the present invention, the parameters considered are amplitude of pressure pulsation above the prescribed threshold (calibratable) and its count exceeding the prescribed threshold (calibratable). Further, how fast the system pressure increases during the system preparation state, i.e. the time it takes to progress from point x value to y value is less than the prescribed threshold (calibratable). Here, pressure points such as x and y are calibratable thresholds and refer to system pressure in Hpa or other suitable units. The controller 110 also makes the decision to validate the pressure samples before making the decision that the filter 106 is missing. (Excludes the samples if the samples are connected to the air entry).

[0024] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.
, Claims:We claim:
1. A controller (110) to detect absence of filter (106) in an Exhaust Gas Treatment (EGT) system (100) of a vehicle, said EGT system (100) comprises:
a tank (102) storing Diesel Exhaust Fluid (DEF);
a supply module (104) to pump said DEF from said tank (102) to a dosing module (108) with a filter (106) therebetween,
at least two conduits, namely, a delivery conduit (112) and a backflow conduit (114), fluidly connects said filter (106) to said dosing module (108) and said tank (102), respectively,
a pressure sensor (116) to measure system pressure, and
said controller (110) connected to said pressure sensor (116) and configured to
activate said supply module (104) to pump DEF to said dosing module (108), characterized in that,
detect absent/missing filter (106) based on at least one parameter derived from signal read by said pressure sensor (116) while said DEF is being pumped by said supply module (104).

2. The controller (110) as claimed in claim 1, wherein said parameter is at least one selected from a group comprising an amplitude of pressure pulses, a count of said amplitude, and a time for pressure increase from x value to y value.

3. The controller (110) as claimed in claim 2 configured to compare said parameter with respective threshold value, wherein a threshold amplitude is considered for said amplitude of each pressure pulses, a threshold count is considered for said count of amplitudes, and a threshold time is considered for said time for pressure increase from x value to y value.

4. The controller (110) as claimed in claim 1, wherein said pressure sensor (116) is connected to said backflow conduit (114).

5. The controller (110) as claimed in claim 1 is a control unit internal to said vehicle and external to said vehicle, wherein said internal control unit is any one of an Engine Control Unit and an Exhaust Control Unit, and said external control unit is a server, a cloud or a diagnostic device connected through any one of a wired and wireless means.

6. A method for detecting absence of a filter (106) in an Exhaust Gas Treatment (EGT) system (100) of a vehicle, said EGT system (100) comprises a tank (102) storing Diesel Exhaust Fluid (DEF), a supply module (104) to pump said DEF from said tank (102) to a dosing module (108) through a filter (106), at least two conduits, namely, a delivery conduit (112) and a backflow conduit (114), fluidly connects said filter (106) to said dosing module (108) and said tank (102), respectively, and a pressure sensor (116) to measure a system pressure, said method comprises the steps of,
activating said supply module (104) to pump DEF from said tank (102) to said dosing module (108), characterized by,
detecting absent/missing filter (106) based on at least one parameter derived from signal read by said pressure sensor (116) while pumping said DEF.

7. The method as claimed in claim 6, wherein said parameter is at least one selected from a group comprising an amplitude of pressure pulses, a count of said amplitude, and a time for pressure increase from x value to y value.

8. The method as claimed in claim 7 comprises comparing said parameter with respective threshold value, wherein said amplitude of each pressure pulses is compared with a threshold amplitude, said count of amplitude is compared with a threshold count, and said time for pressure increase from x value to y value is compared against a threshold time.

9. The method as claimed in claim 6, wherein said pressure sensor (116) is connected to said backflow conduit (114).

10. The method as claimed in claim 6 is a control unit internal to said vehicle and external to said vehicle, wherein said internal control unit is any one of an Engine Control Unit and a Exhaust Control Unit, and said external control unit is a server, a cloud or a diagnostic device connected through any one of a wired and wireless means