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 to a controller and method to detect ageing/aging of a Three-Way Catalyst (TWC) in an exhaust conduit of a vehicle.

Background of the invention:
[0002] A Three-Way Catalysts (TWC) is an apparatus that reduce the emissions of harmful gases from the combustion of gasoline fuel in automobiles. The TWC convert carbon monoxide, hydrocarbons, and nitrogen oxides into carbon dioxide, water, and nitrogen, respectively. They require a precise control of the air-fuel ratio to maintain their efficiency and durability. An On-board Diagnostics (OBD) is a system that monitors and reports the status of the vehicle’s components and systems. The OBD can detect any malfunction or deterioration of the three-way catalysts and alert the driver by illuminating the Malfunction Indicator Light (MIL), also known as the check engine light. The system provides the solution to monitor the life of TWC and helps reporting the issue to the end user by turning on the MIL. The current solution for catalyst monitoring uses O2 measuring probes to detect the oxygen content post catalyst and based on the amplitudes or active response of the sensor, the catalyst ageing is reported.

[0003] According to a prior art US20210102507, methods and systems for catalyst monitoring enablement is disclosed. Methods and systems are provided for enabling diagnostics of an exhaust catalyst regardless of a level of oxygen stored in the catalyst. In one example, a method may include initiating diagnostics of the catalyst in response to an oxygen sensor coupled downstream of the catalyst recording a measurement that crosses a stoichiometric air-fuel ratio output more than a threshold number of times.

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 a controller to detect aging of a Three-Way Catalyst (TWC) in a vehicle, according to an embodiment of the present invention, and
[0006] Fig. 2 illustrates a signal of an oxygen sensor positioned downstream of the TWC, according to an embodiment of the present invention, and
[0007] Fig. 3 illustrates a method flow diagram for detecting the aging of the TWC in the vehicle, according to the present invention.

Detailed description of the embodiments:
[0008] Fig. 1 illustrates a block diagram of a controller to detect aging of a Three-Way Catalyst (TWC) in a vehicle, according to an embodiment of the present invention. A gasoline automobile/vehicle 100 consists of the three-way catalyst (TWC) 106 to convert the harmful gases to less harmful which are coming out of an engine 102 due to incomplete combustion. A catalyst monitoring control system or the controller 110 takes input, primarily from the oxygen sensor 116 positioned downstream position of the TWC 106.

[0009] The controller 110 makes use of the principle of OSC of the TWC 106. The TWC 106 consists of a ceramic or metallic substrate coated with a thin layer of washcoat that contains Precious Group Metals (PGM) such as Platinum, Palladium and Rhodium. The washcoat also contains oxygen storage components (OSC) such as cerium oxide that can store and release oxygen as needed. The TWC 106 operates in a narrow range of air-fuel ratio around the stoichiometric point, where the amount of oxygen and fuel are balanced. The TWC 106 is able to perform three main reactions: oxidation of carbon monoxide (CO) and hydrocarbons (HC) to carbon dioxide (CO2) and water (H2O), and reduction of nitrogen oxides (NOx) to nitrogen (N2). These reactions are exothermic, where they release heat to the surroundings. The exothermic temperature of the TWC 106 depends on several factors, such as the composition and loading of the wash coat, the inlet gas temperature, the air-fuel ratio, the flowrate, and the catalyst aging and the ambient conditions.

[0010] The exothermic reactions that occur within the TWC 106 are as follows:
Oxidation of CO: CO + 0.5 O2 ? CO2 + heat
Oxidation of HC: CnHm + (n + m/4) O2 ? n CO2 + m/2 H2O + heat
Reduction of NOx: NO + CO ? 1/2 N2 + CO2 + heat

[0011] The oxidation reactions require oxygen to proceed, while the reduction reaction consumes oxygen. Therefore, the TWC 106 needs to balance the oxygen supply and demand by using the OSC. When there is excess oxygen in the exhaust gas, the OSC can store some of it for later use. When there is a lack of oxygen in the exhaust gas, the OSC can release some of it to maintain the oxidation reactions. The OSC also helps to buffer the fluctuations in the air-fuel ratio and prevent rapid changes in the catalyst temperature.

[0012] The catalyst aging is a phenomenon that reduces the catalytic activity and performance over time. The main causes of catalyst aging are thermal degradation, chemical poisoning, and mechanical damage. Thermal degradation occurs when the TWC 106 is exposed to high temperatures for prolonged periods, which can cause sintering of the PGM particles, loss of washcoat porosity, phase transformation of the OSC and washcoat support, and decrease in surface area. The chemical poisoning occurs when some contaminants in the exhaust gas or fuel, such as sulfur, phosphorus, lead, zinc, and silicon, bind to the active sites of the PGM or OSC and block their activity. A mechanical damage occurs when the TWC 106 is subjected to vibrations, shocks, or thermal stresses, which can cause cracks, fractures, or detachment of the washcoat from the substrate.

[0013] According to the present invention, the controller 110 to detect aging of the Three-Way Catalyst (TWC) 106 in the vehicle 100 is provided. The vehicle 100 comprises at least one oxygen sensor 116 positioned downstream the TWC 106 in the exhaust conduit 104 of the vehicle 100. The controller 110 configured to receive signal from the oxygen sensor 116, characterized in that, determine a frequency of the received signal, and detect ageing of the TWC 106 based on the comparison of the frequency determined and a threshold frequency 120.

[0014] According to an embodiment of the present invention, the controller 110 is for a vehicle 100 comprising Single Lambda Control System (SLSC) where one oxygen sensor 116 is used for dual operations/functions. The oxygen sensor 116 is the only sensor downstream of the TWC 106 to perform dual functions, namely lambda control and detecting ageing of the TWC 106.

[0015] According to an embodiment of the present invention, the oxygen sensor 116 is either a heated oxygen sensor 116 or unheated oxygen sensor 116. The oxygen sensor 116 is referred to as O2 sensor, air-fuel ratio sensor, lambda sensor and the like.

[0016] According to an embodiment of the present invention, the signal from oxygen sensor 116 is considered for ageing detection during presence of predetermined conditions of the engine 102 with respect to parameters comprising engine speed, engine load and lambda values. The parameters are detected by respective sensors 112 such as engine speed sensor, throttle position sensor and oxygen sensor 116, respectively. In other words, the controller 110 monitors the presence of a predetermined operating zone of the engine 102 of the vehicle 100 and a stoichiometric air-fuel ratio. A signal from an auxiliary oxygen sensor 114 is used if available, otherwise the signal from the oxygen sensor 116 itself is used. The auxiliary oxygen sensor 114 is positioned upstream of the TWC 106. Further, if the signal from the oxygen sensor 116 is used, then the system corresponds to a Single Lambda Control System (SLCS). Thus, the lambda control and diagnosis of the TWC 106 is performed by the single oxygen sensor 116 which is positioned downstream of the TWC 106.

[0017] According to an embodiment of the present invention, the controller 110 processes the signal from the oxygen sensor, specific to ageing detection, during predetermined conditions (indicated above) of a drive cycle. The part of the drive cycle which are under steady state conditions are considered for determination of ageing of the TWC 106. The steady state conditions are those where the TWC 106 conversion is stable 106. The conditions considered for the drive cycle are for example, only at Lambda 1 (absolute or on average, preferably when the lambda = 0.99 to 1.01 on average (can be lot narrower as-well)), engine operating temperature is within permissible range, and there is constant absolute air-charge/mass flow. The lambda value is measured by the lambda/O2/ oxygen sensor 116. Similarly, other parameters of the engine 102 such as air mass flow rate, engine temperature, manifold air pressure and the like are measured by respective sensors 112 such as a flow rate sensor, engine temperature sensor, a manifold air pressure sensor, and the like. The stable operating zones of the engine 102 are some of the other conditions that are necessary. In addition, various inputs such as air intake temperature, ambient temperature, gradients/elevation, fuel injection parameters are also considered whenever required for considering the operating zones of the engine 102.

[0018] According to the present invention, the TWC 106 is any one of a single brick catalyst and a multi brick catalyst. The oxygen sensor 116 is positioned after at least a first positioned brick in the multi brick catalyst. The single brick catalyst and the multi brick catalyst are of same or different capacity.

[0019] 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 one which comprises input interface, output interfaces having pins or ports, the memory element 108 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 108 is pre-stored with logics or instructions or programs or applications or modules/models and/or threshold values/ranges, reference values, threshold frequency 120, predefined/predetermined criteria/conditions, 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 such as transceivers 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. The controller 110 is either the existing control unit of the vehicle 100 such as Engine Control Unit (ECU) or a dedicated control unit interfaced with the existing control unit.

[0020] Further, the processor may be implemented as any or a combination of one or more microchips or integrated circuits interconnected using a parent board, hardwired logic, software stored in the memory element 108 and executed by a microprocessor, firmware, an application specific integrated circuit (ASIC), and/or a field programmable gate array (FPGA). The processor is configured to exchange and manage the processing of various Artificial Intelligence (AI) modules.

[0021] According to an embodiment of the present invention, the controller 110 is implementable in different types of configurations of TWC 106. The configurations are shown with engine 102 in left and exhaust conduit 104 as a line to the right. In a first configuration 122, the TWC 106 is single and big, the oxygen sensor 116 is positioned downstream of the TWC 106. In a second configuration 124, the TWC 106 is tandem (two small catalysts 106 in a single outer casing or two small catalysts with negligible distance between them). The oxygen sensor 116 is positioned downstream of the second brick of the TWC 106. The oxygen sensor 116 is also possible to be positioned in between the bricks of the tandem catalyst, shown in dotted pattern. In a third configuration 126, the TWC 106 is split, and the oxygen sensor 116 is positioned downstream of the first brick of the TWC 106. The oxygen sensor 116 is also possible to be positioned after the last brick of the split type TWC 106, shown in dotted patterns. The oxygen sensor 116 shown in dotted pattern is to depict alternate position. In all the three configurations, the first configuration 122, the second configuration 124 and the third configuration 126, the oxygen sensor 116 is also possible to be positioned on the exhaust conduit 104 after the TWC 106 based on requirement. Thus two positions are shown, in a first position the oxygen sensor 116 is positioned on a housing of the TWC 106, and in a second position, the oxygen sensor 116 is positioned in the exhaust conduit 104 away from the housing and downstream of the TWC 106 but at a distance which does not adversely affect the sensing of the oxygen sensor 116.

[0022] According to an embodiment of the present invention, the vehicle 100 is any one of a two-wheeler such as motorcycle, three-wheeler such as auto-rickshaws, a four wheeler such as car and other vehicles 100 where the use of TWC 106 is done. Further, the vehicle 100 runs on at least one fuel selected from a group comprising a gasoline/petrol, an ethanol blended with gasoline (E0-E100), a Compressed Natural Gas (CNG), a Liquefied Petroleum Gas (LPG) and the like.

[0023] Fig. 2 illustrates a signal of an oxygen sensor positioned downstream of the TWC, according to an embodiment of the present invention. A graph 200 shows the plots of the signal read/detected by the oxygen sensor 116 in typical two-wheeler vehicle 100. The X-axis 204 is time in suitable units and Y-axis 202 is oxygen sensor 116 voltage signal in suitable units such as volts. A first plot 206 shows the signal from the oxygen sensor 116 in solid line when the TWC 106 is new/fresh. A second plot 208 shows the signal from the same oxygen sensor 116 in dashed line when the TWC 106 has aged/deteriorated. The second plot 208 shows the increase in frequency of the signal. Further in time period 210 as indicated in the graph 200, the first plot 206 has two cycles, whereas in the second plot 208 has four cycles within the same time period, indicating the increase in the frequency. The graph 200 and the plots are not in scale and are just shown for understanding. The same must not be understood in limiting manner.

[0024] Since the frequency of the signal is affected by operating points of the vehicle 100, the controlling action and diagnosis is conducted on operating zones basis. The optionally includes include lots of corrections, scaling, smoothening of acquired signals at a defined cycle to perform diagnosis.

[0025] According to the present invention, a working of the controller 110 is explained. Consider a motorcycle with SLSC system is installed for lambda control and diagnosis of the TWC 106. When the driver/rider drives/rides the motorcycle, the controller 110 monitors the operating conditions/zones of the engine 102 and when the operating conditions are favorable or are met with predetermined conditions, the controller 110 starts monitoring the signal from the oxygen sensor 116. The controller 110 receives the signal and determines the frequency of the signal. The determined frequency is compared with the threshold frequency 120, stored in the memory element 108, and detects the ageing of the TWC 106. The controller 110 is able to determine level of the ageing based on multiple threshold frequencies stored in the memory element 108. Once detected, the controller 110 informs the rider/driver on the instrument cluster through audio, video, light or haptic feedback. Alternatively, the controller 110 sends the information to external computer such as server/cloud or smartphone for later usage or processing or sending alerts.

[0026] Fig. 3 illustrates a method flow diagram for detecting the aging of the TWC in the vehicle, according to the present invention. The vehicle 100 comprises the oxygen sensor 116 with or without the heating element, in the exhaust conduit 104. The method comprises plurality of steps of which a step 302 comprises receiving, by the controller 110, signal from the oxygen sensor 116. The method is characterized by a step 304 which comprises determining, by the controller 110, a frequency of the received signal. A step 306 comprises detecting, by the controller 110, ageing of the TWC 106 based on comparison of the frequency determined and the threshold frequency 120. The threshold frequency 120 is stored in the memory element 108 of the controller 110. The oxygen sensor 116 is the only sensor and performs dual functions, namely lambda control and detecting ageing of the TWC 106.

[0027] According to the method, the signal from the oxygen sensor 116 is considered for ageing detection during presence of predetermined conditions of the engine 102 with respect to parameters comprising engine speed, engine load and lambda values. The parameters are detected by respective sensors.

[0028] The oxygen sensor 116 is installed in at least downstream position of the TWC 106. Further, the TWC 106 is any one of the single brick catalyst and the multi brick catalyst. The oxygen sensor 116 is positioned after at least the first positioned brick in the multi brick catalyst.

[0029] According to the present invention, the method is implementable/usable in vehicle 100 using TWC 106 comprising but not limited to the two-wheeler such as motorcycle, the three-wheeler such as auto-rickshaws, the four wheeler such as a car and multi-wheel vehicles.

[0030] According to the present invention, the controller 110 and method to detect the ageing of TWC 106 using in a Single Lambda Control System (SLSC) is disclosed. The inventive step or technical advantage of the preset invention comprises the use of single close loop heated oxygen sensor 116 placed downstream of the TWC 106, but instead of sensing the oxygen content and reporting the catalyst ageing, the frequency of the signal is analyzed. The present invention does not require any hardware changes or additional cost compared to the previous state of arts, but only require a small software/program addition to the controller 110. Alternatively the existing control unit of the vehicle 100 is replaced with the new controller 110 as per the present invention. The controller 110 and method monitors the ageing of the TWC 106 as per the legislation requirements and fulfill the In-Use Monitor Performance Ratio (IUMPR) standards. Further, the controller 110 and method diagnoses the issue pertaining to the TWC 106 to the end user by turning ON the MIL.

[0031] According to the present invention, by monitoring the TWC 106, the environmental impact of automobile emissions is possible to be reduced by ensuring that the catalysts are working properly and efficiently. This also enhances the fuel economy and performance of the vehicle 100. The OBD helps find and fix any problem with the TWC 106, such as damage, contamination, or aging. Further, the OBD helps technicians to perform timely and accurate repairs and prevent further damage to the engine 102 or other components. The OBD also helps comply with the emission regulations and standards that are becoming increasingly stringent in many countries. The OBD can provide evidence of the emission performance of the vehicle 100 and alert the authorities if any tampering or modification of the catalysts has occurred. The solution in the present invention is defined and utilized in the single lambda sensor control system and is not limited to the same. Any system which utilizes the downstream oxygen sensor 116 signal for lambda control based on switching voltage can be implemented with the above stated catalyst age monitoring/detection system.

[0032] 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 ageing of Three-Way Catalyst (TWC) (106) in a vehicle (100), said vehicle (100) comprises an oxygen sensor (116) positioned downstream said TWC (106) in an exhaust conduit (104) of said vehicle (100), said controller (110) configured to,
receive signal from said oxygen sensor (116), characterized in that,
determine a frequency of said received signal, and
detect ageing of said TWC (106) based on comparison of the frequency determined and a threshold frequency (120).

2. The controller (110) as claimed in claim 1, wherein said oxygen sensor (116) is the only sensor and performs dual functions, namely lambda control and detecting ageing of said TWC (106).

3. The controller (110) as claimed in claim 1, wherein said signal from said oxygen sensor (116) is considered for ageing detection during presence of predetermined conditions of an engine (102) of said vehicle (100) with respect to parameters comprising engine speed, engine load and lambda values, said parameters are detected by respective sensors (112).

4. The controller (110) as claimed in claim 1, wherein said TWC (106) is any one of a single brick catalyst and a multi-brick catalyst, wherein in case of said multi-brick catalyst, said oxygen sensor (116) is positioned after at least a first positioned brick of said multi-brick catalyst.

5. The controller (110) as claimed in claim 1 is usable in vehicle (100) using TWC (106) comprising but not limited to a two-wheeler such as motorcycle, three-wheeler such as auto-rickshaws, a four wheeler such as a car and multi-wheel vehicles.

6. A method for detecting ageing of a Three-Way Catalyst (TWC) (106) in a vehicle (100), said vehicle (100) comprises an oxygen sensor (116) positioned downstream said TWC (106) in an exhaust conduit (104) of said vehicle (100), said method comprising the steps of,
receiving signal from said oxygen sensor (116), characterized by,
determining a frequency of said received signal, and
detecting ageing of said TWC (106) based on comparison of the frequency determined and a threshold frequency (120).

7. The method as claimed in claim 6, wherein said oxygen sensor (116) is the only sensor and performs dual functions, namely lambda control and detecting ageing of said TWC (106).

8. The method as claimed in claim 6, said signal from said oxygen sensor (116) is considered for ageing detection during presence of predetermined conditions of an engine (102) of said vehicle (100) with respect to parameters comprising engine speed, engine load and lambda values, said parameters are detected by respective sensors (112).

9. The method as claimed in claim 6, wherein said TWC (106) is any one of a single brick catalyst and a multi-brick catalyst, wherein in case of said multi-brick catalyst, said oxygen sensor (116) is positioned after at least a first positioned brick of said multi-brick catalyst.

10. The method as claimed in claim 6 is usable in vehicle (100) using TWC (106) comprising but not limited to a two-wheeler such as motorcycle, three-wheeler such as auto-rickshaws, a four wheeler such as a car and multi-wheel vehicles.