Description: METHOD AND SYSTEM FOR INCREASING FUEL ECONOMY BY INSTANTANEOUS CATALYST HEALTH PREDICTION
FIELD OF INVENTION:
[001] The present subject matter described herein, relates to a method and a system for increasing fuel economy by determining catalyst health of the exhaust after treatment system of the vehicle, and, in particular, to method and a system which determines required leanness in the internal combustion engine based on the catalyst health of catalytic converter of the exhaust after treatment system. In more particularly, the present subject matter relates to a method and a system which determines the required leanness based on health of the catalyst health in the catalytic converter in the exhaust system and the system actuates having a pressurized transfer chamber and a plurality of electrical control valves located at the upstream and the downstream of transfer tube to re-circulate the exhaust gas multiple times into the catalytic converter for complete conversion of engine out pollutants.
BACKGROUND AND PRIOR ART:
[002] Internal combustion engines use a mixture of fuel and air to generate combustion gases that apply a driving force to a component of the engine. Subsequently, the combustion gases exit the engine as an exhaust, which may be subject to exhaust treatment systems that include one or more catalytic converters to reduce the emissions of nitrogen oxides (NOX), hydrocarbons (HC), carbon monoxide (CO), and other emissions.
[003] In the internal combustion (IC) engines, the Engine Control Unit (ECU) controls the fueling in order to achieve stoichiometric engine operation. The stoichiometric mixture is the ideal air fuel ratio for an IC engine. Due to regular usage of the IC engine, the post combustion exhaust gas treatment system (catalytic converter) gets aged, thus in conventional IC engines, the ECU monitors the catalytic converter health. The health of the catalytic converter is monitored and judged by ECU by using the signals of Pre catalyst gas sensor (Front O2 Sensor) and Post catalyst gas sensor (Rear O2 sensor) and oxygen storage capacity of the catalytic converter as illustrated in the US patent application US20160169136 A1.
[004] In conventional IC engines, when the ECU detects that the catalytic converter has deteriorated or aged then ECU displays a malfunctioning lamp on the instrument cluster for the driver. Therefore, catalyst aging and deterioration is a serious problem in the internal combustion engines. These degradations may cause engines to fall out of emissions compliance and decreases the fuel efficiencies. Conventional catalyst maintenance includes periodic replacement of the catalyst or the catalytic converter after a given period of time.
[005] Further, upon detection of the malfunction, the ECU detects that the catalytic converter has deteriorated. In order to correct the health of the catalytic converter, the ECU either injects urea or richer fueling with respect to stoichiometric operation in order to prevent the production of Nox emissions. Richer mixture prevents high concentration of Nox in tail pipe emissions even after deterioration.
[006] As known, if health of the catalytic convert is not good, the ECU injects fuel richer mixture of fuel and air to avoid generation of NOx emissions in the exhaust gases. Therefore, the ECU can improve the efficiency of the internal combustion engine by controlling the air-to-fuel ratio of the IC engine, which represents the amount of air provided to the IC engine relative to the amount of fuel provided to the IC engine.
[007] Therefore the major technical problem with the existing ECU system in coupling with the exhaust system is that it increases the fuel consumption by increasing the fuel and air mixture to avoid NOx production in the exhaust gases.
[008] In view of the above, it is beneficial to have an exhaust system which can be control by the ECU to reduce NOx production in the exhaust gases when health of the catalytic converter is not good and improve the fuel and air mixture for leanness of the IC engine. Therefore, there is a need in the art to provide an a method and a system that is more simple and inexpensive, and which can be implemented in the ECU to control the exhaust system of vehicle to reduce the NOx production and ideal air fuel ratio for the IC engine.
OBJECTS OF THE INVENTION:
[009] The principal object of the present invention is to detect health of the catalyst of the catalytic converter and the IC engine to improve the fuel efficiency.
[0010] Another object of the present subject matter is to provide a method and a system in Engine Control Unit (ECU) to determine health of the catalytic converter and the engine to be good (not deteriorated), and to switch the fueling to leaner operation to improve the fuel efficiency.
[0011] Another object of the present subject matter is to provide ECU to judge the instantaneous intermediate health status of the Engine and catalyst, in order to interpolate and decide the exact leanness to be provided for maximizing fuel economy benefit to the IC engine without compromising on emissions.
[0012] Yet another object of the present invention is to reduce NOx generation in the catalytic converter without any extra fuel injection.
[0013] Yet another object of the present invention is to provide a simple and inexpensive system for improving the fuel efficiency by judging health of the catalyst in the catalytic converter.
SUMMARY OF THE INVENTION:
[0014] The subject matter disclosed herein relates to a method and a system for leaning fuel air mixture in internal combustion (IC) engine and converting IC engine emissions into allowable limits when health of the catalytic converter is not good. The system is implemented in the Engine Control Unit (ECU) of the vehicle. The ECU has a processor which is communicatively coupled with hardware interface and a memory for receiving and processing various inputs from the sensor to determine health of the catalyst. Further, the ECU controls the exhaust system for leaning of the fuel air mixture. The ECU determines health of catalyst of catalytic converter based on inputs received from exhaust mass gas flow sensor and catalyst temperature sensor and compares it with the stored threshold value to evaluate the health of the catalytic converter. Secondly, the ECU determines health of the catalyst of the catalytic converted based on inputs received from front O2 sensor signal and rear O2 sensor signal during steady state operation. Thirdly, the ECU determines health of the catalyst of the catalytic converter based on catalyst temperature rising up pattern during cold start of the IC engine. Fourthly, the ECU determines health of the catalyst of the catalytic converter based on rear O2 sensor signal voltage increment trend after fuel cut revival. Finally, the ECU determines health of the catalyst of the catalytic converter based on average voltage values of the front O2 sensor and the rear O2 sensor. Further, the ECU determines the health of the engine and vehicle based on various critical and non critical parameters. Furthermore, the ECU takes the input from the driver for driving mode. Based on all above determined health of catalyst and engine, the ECU controls the working of the exhaust system.
[0015] The exhaust system of the vehicle has a plurality of sensor and actuators which are communicatively coupled with the ECU via hardware interface. The exhaust system has a transfer tube to capture emission passes from the catalytic converter and re-circulating the captured emissions into the catalytic converter for further treatment. The transfer tube has two electrical valves provided at upstream end and downstream end. The ECU controls the opening and closing of the electrical valves based on the determined health of the catalyst and the engine for capturing of the emissions in the transfer tube and releasing of the captured emissions in the catalytic converter for further treatment of emissions. Therefore, in the present system and method, the richer fuel mixture is not required to avoid generation of NOx and unburned carbon particles in the emissions. Accordingly, the ECU leans fuel air mixture by controlling the opening and closing of the electrical valves of the transfer tube based on the determined health of the catalyst of the catalytic converter and engine to avoid generation of NOx.
[0016] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0018] Fig. 1 illustrates an exhaust system with Engine Control Unit along with hardware for reducing engine emissions and increasing fuel efficiency, in accordance with an embodiment of the present subject matter;
[0019] Fig. 2 illustrates system of with embodiments of the Logic which the Engine control unit operates on to increase the fuel efficiency, in accordance with an embodiment of the present subject matter;
[0020] Fig. 3 illustrates schematic diagram elaborating how the Instantaneous health of the catalyst is judged, in accordance with an embodiment of the present subject matter;
[0021] Fig. 4 illustrates schematic diagram elaborating how the ECU logic of Instantaneous health of the catalyst and engine is judged, in accordance with an embodiment of the present subject matter;
[0022] Fig. 5 illustrates schematic diagram elaborating how the ECU stores the desired data for monitoring the instantaneous health of the catalyst and engine in accordance with an embodiment of the present subject matter;
[0023] Fig. 6 illustrates method of determining health of the catalyst in the catalytic converter, in accordance with an embodiment of the present subject matter; and
[0024] Fig. 7 illustrates Engine control Unit with embodiments to determine and control flow of exhaust gases in the exhaust chamber to increase fuel efficiency, in accordance with an embodiment of the present subject matter.
[0025] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0026] The subject matter disclosed herein relates to a method and a system for leaning fuel air mixture in internal combustion (IC) engine and converting IC engine emissions into allowable limits when health of the catalytic converter is not good. The system is implemented in the Engine Control Unit (ECU) of the vehicle. The ECU has a processor which is communicatively coupled with hardware interface and a memory for receiving and processing various inputs from the sensor to determine health of the catalyst. Further, the ECU controls the exhaust system for leaning of the fuel air mixture. The ECU determines health of catalyst of catalytic converter based on inputs received from exhaust mass gas flow sensor and catalyst temperature sensor and compared it with the stored threshold value to evaluate the health of the catalytic converter. Secondly, the ECU determines health of the catalyst of the catalytic converted based on inputs received from front O2 sensor signal and rear O2 sensor signal during steady state operation. Thirdly, the ECU determines health of the catalyst of the catalytic converter based on catalyst temperature rising up pattern during cold start of the IC engine. Fourthly, the ECU determines health of the catalyst of the catalytic converter based on rear O2 sensor signal voltage increment trend after fuel cut revival. Finally, the ECU determines health of the catalyst of the catalytic converter based on average voltage values of the front O2 sensor and the rear O2 sensor. Further, the ECU determines the health of the engine and vehicle based on various critical and non critical parameters. Furthermore, the ECU takes the input from the driver for driving mode. Based on all above determined health of catalyst and engine, the ECU controls the working of the exhaust system.
[0027] The exhaust system of the vehicle has a plurality of sensor and actuators which are communicatively coupled with the ECU via hardware interface. The exhaust system has a transfer tube to capture emission passes from the catalytic converter and re-circulating the captured emissions into the catalytic converter for further treatment. The transfer tube has two electrical valves provided at upstream end and downstream end. The ECU controls the opening and closing of the electrical valves based on the determined health of the catalyst and the engine for capturing of the emissions in the transfer tube and releasing of the captured emissions in the catalytic converter for further treatment of emissions. Therefore, in the present system and method, the richer fuel mixture is not required to avoid generation of NOx and unburned carbon particles in the emissions. Accordingly, the ECU leans fuel air mixture by controlling the opening and closing of the electrical valves of the transfer tube based on the determined health of the catalyst of the catalytic converter and engine to avoid generation of NOx.
[0028] The Engine control unit has engine health detection system and catalyst health detection system. The catalyst health detection system determines the health of the catalyst based on several parameters, such as catalyst temperature, signals in front and rear O2 sensor, voltage increment trend in rear O2 sensor after fuel cut revival. Based on the health of the catalyst, the ECU determines the correct amount of leanness, i.e., fuel air mixture is to be supplied to the vehicular engine without compromising of tail pipe emissions, so as to enhance efficiency by reducing real time fuel consumption along with reduced carbon and NOx foot prints.
[0029] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0030] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0031] The present subject matter discloses a system and a method for judging the instantaneous health of the catalyst of catalytic converter in order to determine the correct amount of leanness, i.e., fuel air mixture to be supplied to the vehicular engine without compromising of tail pipe emissions, so as to enhance efficiency by reducing real time fuel consumption along with reduced carbon and NOx foot prints
[0032] The present invention deals with the vehicular engine which requires monitoring of the instantaneous health of the IC engine and catalyst in order to facilitate Engine Control Unit (ECU) to decide the amount of leanness to be applied in the engine to improve the fuel efficiency.
[0033] The combination of the ECU, IC engine, and exhaust system is disclosed in the figure 1. It is well known that fuel injection, fuel air mixture by air intake, and control of exhaust system is done by the ECU. The exhaust system has an exhaust temperature sensor 1 which is mounted just below the IC engine 15 to measure temperature of the emissions. Further, the exhaust system has front O2 sensor 2 and rear O2 sensor 4 to measure flow of oxygen. The exhaust system has a catalytic converter 12 which has a catalytic converter temperature 3 to measure temperature of the catalyst at hot and cold condition. Further, a transfer chamber/tube 11 is provided to store the emissions which are generated during bad health of the catalyst, such as cold start condition. The exhaust system has two electrical valves 13 at end of the transfer tube 11 to entrap the emissions. The exhaust system has an exhaust mass flow measurement valve 8 just after the catalytic converter 12. Further, a post catalyst temperature sensor is provided after the exhaust mass flow measurement valve 8.
[0034] The engine 15 has fuel injectors 5 which are connected to the fuel intake to receive the fuel air mixture. An engine RPM sensor 6 is provided in the engine to measure engine speed of the vehicle. In connection with the engine rotation shaft, a vehicle speed sensor 7 is provided to measure the speed of the vehicle. As known, the engine is controlled by the Engine Control Unit (ECU) 14 which receives inputs from a plurality of sensors/ actuators and based on the inputs generate a logic and control the components. The ECU 14 has several modules to control different components, such as alternator and AC. The present ECU 14 has a module to control the electrical valves 13 of the transfer tube 11 of the exhaust system for reducing the pollutants and improving the fuel efficiency. Based on the inputs from the ECU 14, the electrical valves 13 present at different location in the transfer tube 11 to re-circulate the entrapped emissions in the catalytic converter 12 for further purification.
[0035] The main exhaust pipe is connected with exhaust of engine cylinders in the engine compartment at the front side of vehicle to receive the emissions/exhaust gases and release the emissions in the environment from rear ride of the vehicle. The catalytic converter 12 is provided in the main exhaust pipe after the engine to treat and convert the non-allowable pollutants, such as hydrocarbon, carbon monoxide, and NOx into acceptable pollutants, such as carbon dioxide and H2. In the present exhaust system, the transfer tube 11 is provided in such a manner that the transfer tube 11 receives the emissions passed by the catalytic converter 12 and again re-circulate the emissions into the catalytic converter 12 based on the operation of the electrical valves 13. During the cold start condition, the emissions produce by the engine passes through the catalytic converter 12 and remain un-converted. However these emissions provide some heat to the catalytic converter 12 for raising the operating temperature of the catalytic converter 10 which helps in converting process. Similarly, during the hot start condition, the emissions passes through the catalytic converter 12 heats up the catalytic converter for better conversion.
[0036] One end of the transfer tube 11 is connected with the main exhaust pipe with a Tee connection after the catalytic converter 12. Where other end of the transfer tube 11 is provided above the catalytic converter 12 for releasing the captured emissions in the catalytic converter 12 for further treatment. The transfer tube 11 has one electrical valve 13 at the tee connection and other electrical valve 13 at the connection of the other end of the transfer tube 11 which is just above the catalytic converter 12. Both the electrical valves 13 are controlled by the ECU 14.
[0037] The ECU 14 has a sequence of steps to analyze and determine the catalyst health. Further, the ECU 14 determines the health of the engine, vehicle speed, and inputs by the driver to increase fuel efficiency of the vehicle. Several steps taken by the ECU 14 are:
[0038] The ECU determines the health of catalytic convertor.
[0039] The ECU determines the health of Engine.
[0040] The ECU determines the amount of leanness to be applied by interpolating the fueling defined for a deteriorated catalyst/engine and a healthy catalyst/ engine.
[0041] The ECU further takes the input of the driver request to run in fuel economy mode and actuates the exhaust flow control values of the transfer tube to allow recirculation of the exhaust gas through the catalyst in order to ensure no possibility of increase in tail pipe emissions.
[0042] The ECU 14 determines the health of catalytic convertor.
[0043] Referring to fig. 2 which describes all hardware embodiments which are interrelated with each other to determine health of the catalytic convertor. Further method to determine health of the catalytic converter is also explained with reference to figure 2 and figure 6. The engine control module or instantaneous catalyst health detection system 300 conducts instantaneous monitoring for catalyst 208 of the catalytic convertor 12 in the ECU 14. Based on that judgment, ECU 14 decides whether the fueling system 203 has to be made lean or not. This judgment is made by ECU 14 of the following steps as shown in the figure 6.
[0044] Referring to step 602 of the figure 6, the ECU 14 determines the catalyst 208 age based on the exhaust mass flow and catalyst temperature. The instantaneous catalyst health detection system 300 of the ECU 14 monitors the exhaust gas mass flow and the catalyst temperature using processor and memory of the ECU 14 (as shown in the figure 7). The instantaneous catalyst health detection system 300 measure the exhaust gas flow using an exhaust flow sensor 8 and the catalyst temp is monitored using a temperature sensor 3 located at the center of the catalytic converter 12. The exhaust flow sensor 8 gives exhaust gas mass flow measured 212 to the instantaneous catalyst health detection system 300 in the ECU 14. Further, the temperature sensor 3 gives exhaust gas temperature measured 211 to the instantaneous catalyst health detection system 300 in the ECU 14. As and when the temperature of catalyst 211 exceeds predefined thresholds for example 900o C, the ECU 14 estimates the ageing of the catalyst 208 using the exhaust temperature 211 and exhaust gas mass flow 212. Further, based on the driving pattern of the drivers the catalyst 208 ageing can be determined. Those drivers/customers who drive at lower speeds will have considerably lower rate of degradation of the catalyst with respect to a driver/customer who drives at higher speeds and accelerations.
[0045] Referring to step 604 of the figure 6 and figure 2, the instantaneous catalyst health detection system 300 of the ECU 14 determines age of the catalyst based on front and rear O2 sensor signal during steady state operation. The ECU 14 monitors and saves the difference of sensor signals between the front O2 sensor signal 206 and rear O2 sensor signal 210, during steady state operation, i.e., steady state of engine rpm/vehicle speed/air intake manifold pressure. If the rear O2 voltage signal 210 fluctuates above/ below a predefined threshold and its minimum and maximum fluctuations are more than the limits set in the ECU 14, then based of these interpretations the ECU 14 determines the catalyst 208 health to be good, moderate or deteriorated. The ECU 14 stores its interpretation as referred in Fig 3.
[0046] Referring to step 606 of the figure 6 and figure 2, the instantaneous catalyst health detection system 300 of the ECU 14 determines age of the catalyst based on the catalyst temperature rising up pattern during the event of cold starting operation. During the event of cold engine starting the ECU 14 monitors the catalytic converter 12 temperature sensor signal 3 (209) and stores the same for future reference for comparison. This temperature signal 209 of the catalytic convertor 12 helps the ECU 14 to understand when the catalytic converter has reached its conversion efficiency and after how much time delay. The ECU 14 monitors the catalyst light off temperature pattern at every cold start, and compares the catalyst light off trend based on exhaust flow at different vehicular Odo meter reading. Before the Catalyst light off is reached, catalyst is in unhealthy condition thus the ECU 14 deactivates the strategy of system leanness and gradually based on the light off temperature judgment criteria the ECU 14 determines if the fueling has to be made leaner and by how much amount.
[0047] In cold start condition, the electrical valves are controlled by the ECU 14 for entrapping the emissions to improve the fuel efficiency. The ECU 14 determines the time required for the exhaust gas to reach the electrical valve 13 which is located downstream of the catalytic converter 12. During this time the pressure around the electrical valve 13 is higher than the pressure around the electrical valve 13 which is located at upstream of the catalytic converter 12. The ECU 14 calculates the time required by un-burnt hydrocarbons, Nox, and Co to reach the electrical valve 13 with the help of front and rear O2 sensor signal voltage along with calculated air mass flow across the internal combustion engine with respect to crank angle. When the unacceptable pollutants, such as carbon monoxide (CO), un-burnt hydrocarbons (HC), and nitrous oxide (Nox) that get emitted from the internal combustion engine during cold and hot starting reaches the electrical valve 13, the down electrical valve 13 and the up electrical valve 13 open to trap all the emissions inside the pressurized transfer chamber 13. Once the emissions in allowable limits during cold start of engine are captured inside the transfer tube 11, the electrical valve 13 at the tee connection and electrical valve 13 at the releasing end of the transfer tube 11 is closed. Further, as soon all the starting emissions get captured inside the transfer tube 111 the electrical valve 13 and the electrical valve 13 closes either together or one after the other in order to accommodate leak proof capturing of emissions.
[0048] The ECU monitors the temperature of the catalytic converter 12 and the internal combustion engine. When the temperature of the catalytic converter 12 is above the light-off temperature, i.e., 350o to 450o C, the ECU opens the upper electrical valve 13 and the lower electrical valve 13 to purge captured emissions back into the catalytic converter 12 from the releasing end which equipped with electrical valve 13. If the temperature of the catalytic converter 12 is below the light off-temperature, the ECU 14 keeps the electrical valves 13 close. When the temperature of the catalytic converter 12 is above the light-off temperature, the catalytic converter 12 converts the captured emissions from un-allowable limits to allowable limit by burning the un-acceptable hydrocarbons and carbon dioxide completely. The catalytic converter 12 converts the pollutants from un-allowable limits into pollutants with allowable limits, such as carbon dioxide and H2O. Based on the temperature of the catalytic convert 12, the ECU 14 open and close the electrical valve 13 of the transfer tube 11 to increase temperature of the catalytic converter 12 upto light off temperature for complete purification of the emissions and avoiding generation of NOx. Further, the ECU 14 provides leaner fuel air mixture into the engine 15 as production of NOx is handled by the exhaust system and transfer tube 11 which entraps the emissions for further purification.
[0049] Referring to step 608 of the figure 6 and figure 2, the instantaneous catalyst health detection system 300 of the ECU 14 determines age of the catalyst based on Rear O2 voltage increment trend after Fuel cut revival. During the event of decelerations the ECU 14 stops the fuel injection. This is called deceleration fuel cut. Further after the completion of the event of deceleration fuel cut, the event of fuel revival or reinjection is initiated by the ECU. During the event of fuel revival or reinjection the ECU 14 monitors the rear O2 sensor signal 210. The ECU 14 monitors the time take by the Rear O2 sensor signal 210 to reach a fixed threshold, for example, 0.8 Volts. Based on this time the said ECU 14 determines whether the Instantaneous health of the catalyst 208 of the catalytic converter 12 is good moderate or deteriorated. Based on the determined time, the ECU 14 controls the electrical valves 13 of the transfer tube 11 to entrap emissions and re-circulate the entrapped emissions into the catalytic converter 12 for further purification. Therefore, the ECU 14 can provide leaner fuel air mixture instead of richer fuel mixture in the particular determined time. Accordingly, the ECU 14 improves the fuel efficiency by controlling the electrical valve 13 of the transfer tube 11 for avoiding generation of NOx in the emission. On the other hand, if emissions are not controlled and purified by the transfer tube 11, the ECU 14 has to give richer fuel mixture to avoid generation of the NOx in the emissions.
[0050] During the event of sudden acceleration or fuel cut revival after deceleration of the vehicle, conventionally, extra fuel was provided in order to remove extra O2 from the catalyst of the catalytic converter 11 and the engine in order to avoid NOx production. Generally, the engine fueling becomes a richer during accelerations and fuel cut revival due to which NOx emissions are generated.
[0051] The exhaust system with the ECU 14 reduces generation of NOx during sudden acceleration and deceleration without any extra fuel injection. The ECU 14 determines if there is a sudden acceleration in the engine and immediately operates the electrical valves 13 of the transfer tube 11 to capture the emissions. By the operations of the ECU 14, the transfer tube 11 expels the captured emissions into the upstream of the catalytic converter 12 using the upstream electrical valve 13 in order to remove the access O2 and avoid production of NOx.
[0052] Referring to step 610 of the figure 6 and figure 2, the instantaneous catalyst health detection system 300 of the ECU 14 determines age of the catalyst based on the average voltage values of Front and Rear O2 sensor. The ECU 14 monitors the average values of the operating voltages of both Front (2) 206 and Rear O2 (4) sensors 210, and uses the same to compare the instantaneous health of the catalyst. The instantaneous voltages are again compared with a predefined threshold value, for example, 0.8 Volts. These values are also saved at different Odo meter milestones for future comparisons and references in the table as shown in the figure 5.
[0053] The ECU determines the health of Engine.
[0054] The instantaneous monitoring of the Engine 15 is done by the ECU 14. Based on that judgment, the ECU 14 decides whether the fueling has to be made lean or not. The health of Engine 15 is judged / determined based on a number of factors. These factors can be classified into critical engine parameters and non-critical engine parameters.
[0055] Critical engine parameters ensure the stability and safety of engine, drivability and healthy emissions. The output of the below referred parameters are determined by a set of thresholds by the ECU 14 in order to determine if the engine 15 is in a healthy state of operation or has deteriorated. The critical parameters include, Engine Rpm fluctuation 6 during engine in idling or steady state operation, the exhaust temp 1 during 3000 rpm or max achieved Rpm condition, instantaneous engine oil level, volumetric efficiency, Atmospheric pressure, acceleration, etc. These parameters are logged in the table and monitored by the said ECU 14 for comparisons against fixed thresholds as referred in fig 5.
[0056] Referring to figure 2, the ECU 14 has engine and vehicle health detection system 213 which determines the health of the engine 15 and supplies fuel air mixture based on the health of the engine and vehicle. The ECU 14 manages to change the fuel air mixture by changing the working of the fuel injectors 202 and the air intake manifold 201 to the engine 205 or 15.
[0057] The ECU 14 determines the amount of leanness to be applied by interpolating the fueling defined for a deteriorated catalyst/ engine and a healthy catalyst/ engine. Referring to figure 4, after the ECU 14 has monitored and determined the instantaneous health of both the Engine 15 and the catalytic converter 12. The ECU 14 either interpolates or decides the fueling amount or initiates to use a lean fueling map based on the health status of the engine and catalytic converter. As shown in Fig 4, the ECU 14 determines the catalytic health in scale of 0 to 100% as good. Similarly, the ECU 14 determines the health of the engine in the sale of 0 to 100% as good. Based on health of both of the catalytic converter and the engine, the ECU 14 determines the leanness in the 100% lean to 100% rich map of fuel. Based on the condition of the health of the catalytic converter 12, the ECU 14 operates the electrical valves 13 of the transfer tube 11 to manage good leanness and to improve fuel efficiency by providing leaner fuel air mixture into the engine 15.
[0058] The ECU further takes the input of the driver request to run in fuel economy mode and actuates the exhaust flow control values of the transfer tube to allow recirculation of the exhaust gas through the catalyst in order to ensure no possibility of increase in tail pipe emissions.
[0059] During normal engine operations, the ECU 14 predicts the health of the said engine 15 and the catalyst 14 for deciding that the system should operate leaner and by how much. But in case when the ECU 14 receives a command from the driver to activate the economy mode operation, the said ECU 14 performs the following operation in order to provide maximised fuel economy benefit to the coustomer / driver of the vehicle.
[0060] The ECU 14 determines the deterioration rate of the engine 15 and the catalyst 14; and decides based on the deterioration rate Leanness required to be set in the engine by the ECU. How the health of the catalyst is determined by the ECU 14 is explained in the figure 6. After determining the desired leanness based on the health of the catalyst, the ECU 14 actuates the electrical control valves 13 located upstream and downstream of the transfer tube 11. This allows the exhaust gas to circulate the multiple times in the catalytic converter 12 before exiting out of the tail pipe. Multiple circulations ensure complete conversion of engine out pollutants into stable form. With the help of the said transfer tube valves 13 under operation of ECO mode, the ECU 14 is able to achieve better fuel economy when there is not transfer tube 11 and electrical valves 13 in the exhaust system. The ECU 14 further allows the system to become as lean as possible without any compromise on tail pipe emissions.
[0061] Further, the ECU 14 controls opening and closing of the electrical valves 13 in synchronization with health of engine and catalytic converter to capture more emissions efficiently.
[0062] Figure 7 illustrates the embodiment features of the engine control unit 14 or 700. The ECU 700 has a processor 701, a hardware interface 702, a memory 703, a engine and vehicle health detection system 705, catalyst health detection system 706, fueling system 707 and valve control system 708. The processor(s) 701, may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the processor(s) 701 is configured to fetch and execute computer-readable instructions stored in the memory 703.
[0063] The functions of the various elements shown in the figure, including any functional blocks labeled as “processor(s)”, may be provided through the use of dedicated hardware as well as hardware capable of executing computer readable instructions or logics in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term “processor” should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), non-volatile storage. Other hardware, conventional and/or custom, may also be included.
[0064] The hardware interface 702 may include a variety of software and hardware interfaces, for example, interfaces for peripheral device(s), such as sensors, actuators, and an external memory. The hardware interface 702 is suitable for interfacing with the sensor and actuators as referred in the figure 2. The memory 703 can include any computer-readable medium known in the art including, for example, volatile memory, such as static random access memory (SRAM) and dynamic random access memory (DRAM), and/or non-volatile memory, such as read only memory (ROM), erasable programmable ROM, flash memories, hard disks, optical disks, and magnetic tapes. Generally construction of the ECU 14 is well known in the art. The processor 701 is operatively coupled with the memory 703 and the hardware interface 702 to execute the instructions for running the ECU 14. These instruction or logics may be encoded in the programs that are stored in the memory 703. Further, all the output of the system and calculation of the ECU also stores in the memory 703 for future determinations.
[0065] As shown in the figure 2, the plurality of sensors provides various signals to the ECU 700 via hardware interface 702. Further, the various actuators, such as electrical valves 13 of the transfer tube 11 are controlled by the processor 701 of the ECU 700 based on the instructions of the catalyst health detection system 706 and the engine health detection system 705.
[0066] The catalyst health detection system 706 is module which receives several inputs from the catalytic converter, front and rear O2 sensor, speed of the emissions, temperature of the emissions, and temperature of the catalytic converter to determine health of the catalytic converter as explained with reference to figure 2 and figure 6. Similarly, the engine health detection system 705 is module having computer executable instructions to receive inputs from the engine via various sensors to determine health of the engine. Based on the inputs from the catalyst health detection system 706 and the engine health detection system 705, the ECU 700 determines the leanness, i.e., fuel air mixture for the engine via fueling system 707. The fueling system 707 receives the input of the catalyst health, engine health, and driver’s input for running mode and determines leanness as per figure 4 for the engine to achieve better fuel economy. The processor 701 of the ECU 700 is communicatively coupled with the valve control system 708 to control opening and closing of electrical valves 13 of the transfer tube 11. The electrical valves 13 are coupled with the ECU 700 via hardware interface 702 for smooth and fast communication. The valve control system 708 of the ECU 700 controls the opening and closing of the valves 13 in the transfer tube 11 based on the instructions received from the ECU 700 for better fuel economy.
[0067] It is easy to manufacture the present ECU and exhaust system with transfer tube and electrical valves in the vehicle. The present system is cost efficient as compared to other existing solutions. Further, the present exhaust system is robust which can effectively work in any condition or at any temperature of the engine and catalytic converter to avoid emissions of harmful pollutants into environment. This exhaust system improves the fuel consumption of vehicle in sudden acceleration.
[0068] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. Plural structural components or steps can be provided by a single integrated structure or step. Alternatively, a single integrated structure or step might be divided into separate plural components or steps. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.
[0069] The term “vehicle” as used throughout this detailed description and in the claims refers to any moving vehicle that is capable of carrying one or more human occupants and is powered by any form of energy. The term “vehicle” is a motor vehicle which includes, but is not limited to: cars, trucks, vans, minivans, hatchback, sedan, MUVs, and SUVs.
[0070] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

Claims:We claim:
1. A Engine Control Unit (14, 700) coupled with exhaust system for leaning fuel air mixture in internal combustion (IC) engine (15) and converting IC engine (15) emissions into allowable limits, the Engine Control Unit (ECU) (14, 700) comprising:
a processor (701) communicatively coupled with hardware interface (702) and a memory (703), the processor configured to:
determine (602) health of catalyst (208) of catalytic converter (12) based on inputs received from exhaust mass gas flow (211) and catalyst temperature (209);
determine (604) health of the catalyst (208) of the catalytic converted (12) based on inputs received from front O2 sensor signal (206) and rear O2 sensor signal (210) during steady state operation;
determine (606) health of the catalyst (208) of the catalytic converted (12) based on catalyst temperature (209) rising up pattern during cold start of the IC engine (15);
determine (608) health of the catalyst (208) of the catalytic converted (12) based on rear O2 sensor signal (210) voltage increment trend after fuel cut revival; and
determine (610) health of the catalyst (208) of the catalytic converted (12) based on average voltage values (206, 210) of the front O2 sensor and the rear O2 sensor;
the exhaust system comprising:
a transfer tube (11) to capture emission passes from the catalytic converter (12) and re-circulating the captured emissions into the catalytic converter (12); and
two electrical valves (13) provided at upstream end and downstream end of the transfer tube (11), wherein the ECU (14, 700) controls the opening and closing of the electrical valves (13), based on the determined health of the catalyst (208), for capturing of the emissions in the transfer tube (11) and releasing of the captured emissions in the catalytic converter (12) for further treatment of emissions;
wherein the ECU (14, 700) leans fuel air mixture by controlling the opening and closing of the electrical valves (13) of the transfer tube (11) based on the determined health of the catalyst (208) of the catalytic converter (12).

2. The ECU (14, 700) as claimed in claim 1, wherein the processor (701) coupled with the hardware interface (702) and the memory (703) to determine health of the IC engine (15) based on inputs received from engine rpm sensor (6), vehicle speed sensor (7), exhaust temperature, engine oil level, volumetric efficiency, and acceleration.
3. The ECU (14, 700) as claimed in claim 1, wherein the processor (701) determines (604) health of the catalyst (208) as good, moderate or deteriorate by comparing fluctuation of the rear O2 voltage signal (210) with predefined threshold value in the memory (703) of the ECU (14, 700).
4. The ECU (14, 700) as claimed in claim 1, wherein the ECU (14, 700) leans the fuel air mixture based on the determination (606) by analyzing catalyst light off temperature pattern and comparing the catalyst light off pattern with exhaust flow at different vehicle odo meter reading.
5. The ECU (14, 700) as claimed in claim 1, wherein the ECU (14, 700) monitors temperature of the catalytic converter (12) with the help of sensors,
if the temperature of the catalytic converter (12) is above light-off temperature, the electrical valve (13) opens and slowly purge the captured emissions back into the catalytic converter (12) for treatment and converting the emissions to stable state; and
if the temperature of the catalytic converter (12) is below light off temperature, the electrical valves (13) remain close.
6. The ECU (14, 700) as claimed in claim 1, wherein the ECU (14, 700) monitors by the rear O2 signal during fuel revival and reinjection, and the ECU (14, 700) monitors time taken by the rear O2 sensor signal (210) to reach predefined threshold value,
based on the time taken by the rear O2 sensor signal (210), the ECU (14, 700) determines health of the catalyst (208) of the catalytic converter (12) as good, moderate or deteriorate.
7. A method (600) for leaning fuel air mixture in internal combustion (IC) engine (15) and converting IC engine (15) emissions into allowable limits, the method ( 600) comprising:
determining (602), by Engine Control Unit (ECU) (14, 700), health of catalyst (208) of catalytic converter (12) based on inputs received from exhaust mass gas flow (211) and catalyst temperature (209);
determining (604), by the ECU (14, 700), health of the catalyst (208) of the catalytic converted (12) based on inputs received from front O2 sensor signal (206) and rear O2 sensor signal (210) during steady state operation;
determining (606), by the ECU (14, 700), health of the catalyst (208) of the catalytic converted (12) based on catalyst temperature (209) rising up pattern during cold start of the IC engine (15);
determining (608), by the ECU (14, 700), health of the catalyst (208) of the catalytic converted (12) based on rear O2 sensor signal (210) voltage increment trend after fuel cut revival; and
determining (610), by the ECU (14, 700), health of the catalyst (208) of the catalytic converted (12) based on average voltage values (206, 210) of the front O2 sensor and the rear O2 sensor; and
wherein the determined health of the catalyst (208) use by the ECU (14, 700) to control exhaust system for leaning fuel air mixture in engine (15).
8. The method as claimed in claim 7, wherein the method (600) further comprises:
controlling two electrical valves (13) provided at upstream end and downstream end of the transfer tube (11) in the exhaust system by the ECU (14, 700) based on the determined health of the catalyst (208) of the catalytic converter, the ECU (14, 700) configures to:
open the electrical valve (13) to capture the emissions in the transfer tube (11);
open the electrical valve (13) at upstream slowly to purge the captured emissions in the catalytic converter (12) for complete combustion of un-burnt hydrocarbons and converting the emissions into allowable limits.
9. The method as claimed in claim 7, wherein the ECU (14, 700) decides fueling amount using lean fueling map based on the health status of the engine (15) and the catalytic converter (12).