Claims:We claim:
1. An Engine Control Unit (ECU) (200) for emission performance, the ECU (200) coupled with a plurality of fuel injectors (102) and a front oxygen sensor (103), the ECU (200) comprising:
a misfiring determining unit (212) to determine misfiring percentage in an internal combustion engine (101),
characterized in that
a front oxygen sensor control unit (214) controls detection time of the front oxygen sensor (103) to detect rich or lean air-fuel mixture dynamically based on the determined misfiring percentage in the internal combustion engine (101).

2. The ECU (200) as claimed in claim 1, wherein the front oxygen sensor control unit (214):
compares the determined misfiring percentage of the internal combustion engine (101) with a pre-stored lookup table having predetermined experimented values for the misfiring percentage of the internal combustion engine (101) and corresponding target detection time of the front oxygen sensor (103) to detect the air-fuel mixture is rich or lean;
selects the target detection time of the front oxygen sensor (103) based on the comparison between the determined misfiring percentage of the internal combustion engine (101) with the pre-stored lookup table; and
updates and calibrates the target detection time of the front oxygen sensor (103) based on the selected the target detection time of the front oxygen sensor (103) from the pre-stored lookup table.
3. The ECU (200) as claimed in claim 1, wherein the front oxygen sensor control unit (214):
compares the determined misfiring percentage of the internal combustion engine (101) with a pre-stored lookup table having predetermined experimented values for the misfiring percentage of the internal combustion engine (101) and corresponding target operating voltage (Vopt) of the front oxygen sensor (103);
selects the target operating voltage (Vopt) of the front oxygen sensor (103) based on the comparison between the determined misfiring percentage of the internal combustion engine (101) with the pre-stored lookup table; and
updates and calibrates the target operating voltage (Vopt) of the front oxygen sensor (103) based on the selected the target operating voltage (Vopt) of the front oxygen sensor (103) from the pre-stored lookup table.
4. The ECU (200) as claimed in claims 1-3, wherein the ECU (200) comprises an air-fuel mixture ratio control unit (216) to:
change, based on input from the front oxygen sensor control unit (214), air-fuel mixture ratio (A/F ratio) towards the rich.
5. A method (500) for emissions of an internal combustion (IC) engine (101), the method (500) comprising:
determining (502) misfiring percentage of the internal combustion engine (101);
comparing (504) the determined misfiring percentage of the internal combustion engine (101) with a pre-stored lookup table having predetermined experimented values for misfiring percentage of the internal combustion engine (101) and corresponding target detection time of a front oxygen sensor (103) to detect the air-fuel mixture is rich or lean;
selecting (506) the target detection time of the front oxygen sensor (103) from the pre-stored lookup table; and
updating and calibrating (508) the target detection time of the front oxygen sensor (103) dynamically based on the selected target detection time from the pre-stored lookup table.
6. The method (500) as claimed in claim 5, wherein the method (500) comprising:
comparing (510) the determined misfiring percentage of the internal combustion engine (101) with a pre-stored lookup table having predetermined experimented values for misfiring percentage of the internal combustion engine (101) and corresponding target operating voltage (Vopt) of the front oxygen sensor (103) to detect the air-fuel mixture is rich or lean;
selecting (512) the target operating voltage (Vopt) of the front oxygen sensor (103) from the pre-stored lookup table; and
updating and calibrating (514) the target operating voltage (Vopt) of the front oxygen sensor (103) dynamically based on the selected target operating voltage (Vopt) from the pre-stored lookup table.
7. The method (500) as claimed in claim 5, wherein the method (500) comprises: changing, based on input from the front oxygen sensor control unit (214), the air-fuel mixture ratio (A/F ratio) towards the rich.

Description:A METHOD AND FRONT OXYGEN SENSOR CONTROL UNIT FOR REDUCTION OF EMISSIONS IN AUTOMOBILE
TECHNICAL FIELD
[0001] The present disclosure, in general, relates to an internal combustion engine for improving emissions performance, and in particular, to a method and a device, i.e., an Engine Control Unit (ECU) for reducing emissions by controlling center voltage of front oxygen (O2) sensor in an event when misfire is more than a predefined threshold percentage value.
BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention.
[0003] Today, the automobile industry highly depends on catalyst-based after-treatment technology to match with exhaust emission regulations. With the three-way converter, oxides of nitrogen (NOx) are reduced into simple nitrogen and carbon-dioxide; and Hydrocarbons and carbon monoxide are oxidized to form water and carbon-dioxide.
[0004] In order for a catalyst to best clean up NOx, the A/F ratio must be richer than 14.7:1. However, CO and THC is generated when mixture is rich. For the catalyst to best clean up CO and HC, the A/F ratio must be lean, but NOx is generated when mixture is lean.
[0005] In the automobile, oxygen sensors are positioned in the exhaust system to determine the oxygen content in the exhaust gases and give the determined oxygen content to the Engine Control unit to determine the air-fuel ratio. Closed-loop feedback-controlled fuel injection varies the fuel injector output according to real-time sensor data rather than operating with a predetermined (open-loop) fuel map. With enablement of the injection controlled by the ECU, the emissions can be reduced by reducing both unburnt fuel and oxides of nitrogen entering the atmosphere.
[0006] In order to ensure controlled oxygen cycling, oxygen sensor feedback is used. Generally, two sensors are used where one is front or primary oxygen sensor, which is positioned before the catalytic converter, and a rear or secondary oxygen sensor positioned after the catalytic converter. The front oxygen sensor provides fuel feedback to an Electronic Control Unit (ECU) to decide rich fuelling or lean fuelling. Further, the rear oxygen sensor provides correction to primary feedback of the front oxygen sensor to control fuelling.
[0007] Based on the feedback provided by the front oxygen sensor and rear oxygen sensor, fuelling of the internal combustion engine is controlled by the ECU. If base emissions are on leaner side, lean output signal is generated by front oxygen sensor and rich side fuelling gain signal is triggered by ECU. Similarly, if base emissions are on richer side, output signal is generated by front oxygen sensor & lean side fuelling gain signal is triggered by the ECU. So depending upon rich or lean emissions, either of these two maps should be calibrated.
[0008] In automobile having the front oxygen sensor and the rear oxygen sensor or only having the front oxygen sensor, when a misfire occurs, a large amount of air discharged from the misfiring cylinder causes the sensor output to largely fluctuate to the lean side there by Nox is produced. If the misfire is continued, the air-fuel ratio is largely corrected to the rich side by the lean output of the sensor, and the state becomes excessively rich at the time of normal combustion return. In addition, the air-fuel ratio once in the over-rich state follows the process of gradually decreasing its amplitude while converging to the target air-fuel ratio while being largely shaken alternately on the lean side and the rich side by feedback correction. The air-fuel ratio after the return to the normal combustion is greatly disturbed, and it takes a while until the air-fuel ratio converges to the target air-fuel ratio. During that time, an increase in exhaust emission and a decrease in drivability are caused. In addition, during a misfire the system behaves erratically and this leads to creation of instability in the combustion system thereby disturbing the operation of the complete system. Furthermore, it has been observed that during misfire conditions the NOx emissions increase thereby crossing the predefined threshold value as set by the regulations. In recent times, it has become and essential requirement that the regulatory statutory limits are met and cost of catalyst is lowered with the existing engine hardware and machinery. Misfiring condition in the engine leads to higher NOx emissions and increase in overall costs.
[0009] Therefore, in order to overcome the limitations of the existing provisions, there is need in the art to provide for a method and a device/system reduce NOx emissions during any event of a misfire based on controlling the Front Oxygen sensor or Rear Oxygen sensor or both.
OBJECTS OF THE DISCLOSURE
[0010] It is therefore the object of the invention to overcome the aforementioned and other drawbacks in prior systems used for reduction of emissions in the event of a misfire.
[0011] Another object of the present invention is to control leanness and richness of fuelling during the event of misfire in the engine.
[0012] Another object of the present invention is to reduce the instability of the internal combustion engine occurring due to an event of misfire.
[0013] Another object of the present invention is to reduce the cost of catalyst and meet the NOx emission standards.
[0014] It is another object of the present disclosure to provide a device that restricts generation of more NOx when misfiring event is happening in the internal combustion engine.
[0015] It is another object of the present disclosure to provide a method and a device to negate the negative effect of misfiring on the emissions.
[0016] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.
SUMMARY
[0017] This summary is provided to introduce concepts related to a method and a device to improve emission performance by controlling target detection time and target operating voltage of front oxygen sensor with respect to determined misfiring percentage in an internal combustion engine. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0018] In an embodiment, the present disclosure relates to an Engine Control Unit (ECU) device for reducing emissions, specifically, NOx generation during misfiring event. The ECU device is coupled with a plurality of fuel injectors and a front sensor and a rear sensor. The ECU comprising a misfiring determining unit to determine misfiring percentage in an internal combustion engine and a front oxygen sensor control unit controls detection time of the front oxygen sensor to detect rich or lean air-fuel mixture dynamically based on the determined misfiring percentage in the internal combustion engine.
[0019] In an aspect, the front oxygen sensor control unit compares the determined misfiring percentage of the internal combustion engine with a pre-stored lookup table having predetermined experimented values for the misfiring percentage of the internal combustion engine and corresponding target detection time of the front oxygen sensor to detect the air-fuel mixture is rich or lean; selects the target detection time of the front oxygen sensor based on the comparison between the determined misfiring percentage of the internal combustion engine with the pre-stored lookup table; and updates and calibrates the target detection time of the front oxygen sensor based on the selected the target detection time of the front oxygen sensor from the pre-stored lookup table.
[0020] In an aspect, the front oxygen sensor control unit compares the determined misfiring percentage of the internal combustion engine with a pre-stored lookup table having predetermined experimented values for the misfiring percentage of the internal combustion engine and corresponding target operating voltage (Vopt) of the front oxygen sensor; selects the target operating voltage (Vopt) of the front oxygen sensor based on the comparison between the determined misfiring percentage of the internal combustion engine with the pre-stored lookup table; and updates and calibrates the target operating voltage (Vopt) of the front oxygen sensor based on the selected the target operating voltage (Vopt) of the front oxygen sensor from the pre-stored lookup table.
[0021] In an aspect, the ECU comprises an air-fuel mixture ratio control unit to change, based on input from the front oxygen sensor control unit, air-fuel mixture ratio (A/F ratio) towards the rich.
[0022] In another embodiment the present subject matter relates to a method for improving emissions of an internal combustion (IC) engine. The method comprising determining misfiring percentage of the internal combustion engine; comparing the determined misfiring percentage of the internal combustion engine with a pre-stored lookup table having predetermined experimented values for misfiring percentage of the internal combustion engine and corresponding target detection time of a front oxygen sensor to detect the air-fuel mixture is rich or lean; selecting the target detection time of the front oxygen sensor from the pre-stored lookup table; and updating and calibrating the target detection time of the front oxygen sensor dynamically based on the selected target detection time from the pre-stored lookup table.
[0023] In aspect, the method comprising comparing the determined misfiring percentage of the internal combustion engine with a pre-stored lookup table having predetermined experimented values for misfiring percentage of the internal combustion engine and corresponding target operating voltage (Vopt) of the front oxygen sensor to detect the air-fuel mixture is rich or lean; selecting the target operating voltage (Vopt) of the front oxygen sensor from the pre-stored lookup table; and updating and calibrating the target operating voltage (Vopt) of the front oxygen sensor dynamically based on the selected target operating voltage (Vopt) from the pre-stored lookup table.
[0024] In an aspect, the method includes changing, based on input from the front oxygen sensor control unit, the air-fuel mixture ratio (A/F ratio) towards the rich.
[0025] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
[0026] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[0027] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. 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 and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which:
[0029] Fig. 1 illustrates architecture of Internal Combustion Engine with exhaust gas system and Engine Control Unit (ECU) in a close loop control for controlling fuelling, in accordance with all embodiments of the present disclosure;
[0030] Fig. 2 illustrates architecture of ECU with front and rear oxygen sensor and other health checks in the close loop control for controlling fuelling, in accordance with all embodiments of the present disclosure;
[0031] Fig. 3 illustrate graph of rich side and lean side with target detection time delay to achieve rich air-fuel mixture ratio, in accordance with first embodiment of the present disclosure;
[0032] Fig. 4a illustrates a method for dynamically updating target detection time for rich or lean of air fuel mixture by the front oxygen sensor, in accordance with first embodiment of the present disclosure;
[0033] Fig. 4b illustrates a method for dynamically updating target operating voltage of the front oxygen sensor to make the air-fuel mixture rich to reduce NOx generation, in accordance with first embodiment of the present disclosure;
[0034] Fig. 5 illustrates a method for dynamically updating target operating voltage of the rear oxygen sensor to make the air-fuel mixture rich to reduce NOx generation, in accordance with second embodiment of the present disclosure; and
[0035] Fig. 6 illustrates a method for dynamically updating target fuel enrichment amount and time duration for target fuel enrichment amount to shift air-fuel ratio towards richer side to reduce NOx generation, in accordance with third embodiment of the present disclosure.
[0036] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in a computer-readable medium and executed by a computer or processor, whether or not such computer or processor is explicitly shown.
DETAILED DESCRIPTION
[0037] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0038] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a", “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0040] In addition, the descriptions of "first", "second", “third”, and the like in the present invention are used for the purpose of description only, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include at least one of the features, either explicitly or implicitly.
[0041] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0042] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0043] Micro-Controller: It is a compact integrated circuit designed to govern a specific operation in an embedded system. A typical microcontroller includes a processor, memory and input/output (I/O) peripherals on a single chip. Generally, microcontrollers are designed to be readily usable without additional computing components because they are designed with sufficient on board memory as well as offering pins for general I/O operations, so they can directly interface with sensors and other components.
[0044] Fuel Cut Revival: It is a condition during gear shifting gears when there is no supply of fuel to the engine. After the fuel cut, required fuel is being supplied to the engine for generating power.
[0045] When an internal combustion engine is under high load (e.g. wide open throttle), the output of the oxygen sensors is ignored, and the ECU automatically enriches the mixture to protect the engine, as misfires under load are much more likely to cause damage. This is referred to as an engine running in "open-loop mode".
[0046] During the event of fuel cut revival, both the front oxygen sensor and rear oxygen sensor are inhibited and do not provide any fuel feedback value to the ECU for controlling the fuelling. Accordingly, the ECU supplies air-fuel ratio to control emissions in the engine. The present subject matter works in closed loop control to enrich fuel in the engine based on a fuel cut revival control unit to increase the level of fuel enrichment towards the richer side and increases the time duration for richer side to achieve the required richness to avoid misfiring and generation of NOx.
[0047] When the engine is accelerating at very gently or maintaining a constant speed, for example, in petrol or CNG vehicle, the controlling of fuelling via a plurality of fuel injectors is operating in "closed-loop mode" as shown in fig. 2. When an internal combustion engine is under high load (e.g. wide open throttle), the output of the oxygen sensors are ignored, and the ECU automatically enriches the mixture to protect the engine, as misfires under load are much more likely to cause damage. This is referred to as an engine running in "open-loop mode". The close loop mode is also referring as feedback loop between the ECU and the front and the rear oxygen sensor(s) in which the ECU adjusts the quantity of fuel and expects to see a resulting change in the response of the oxygen sensor. This feedback loop or close loop forces the engine to operate both slightly lean and slightly rich on successive loops, as it attempts to maintain a mostly stoichiometric ratio on average. If the engine forces to run moderately lean, there will be a slight increase in fuel efficiency at the cost of increased NOx emissions, much higher exhaust gas temperatures. With increase in power in the systems running of preferable lean side to have more fuel efficiency can turn into misfires, as well as potential engine and catalytic-converter (due to the misfires) damage, at lean air–fuel ratios. If modifications cause the engine to run rich, then there will be a slight increase in power to a point (after which the engine starts flooding from too much unburned fuel), but at the cost of decreased fuel efficiency, and an increase in unburned hydrocarbons in the exhaust, which causes overheating of the catalytic converter.
[0048] The present subject matter relates a close loop method to control misfire in the engine during demand and maintain stoichiometric to avoid generation of NOx. The present subject matter works in close loop control to delay detection of rich and lean air fuel mixture ratio in the engine based on the front oxygen sensor to make rich air-fuel ratio. The present subject matter also increases the target operating voltage of the front oxygen sensor to control the NOx generation and to avoid misfiring by making rich air-fuel ratio.
[0049] FIG. 1 illustrates an architecture 100 of an internal combustion engine with Engine Control Unit (ECU) coupled with front and rear oxygen sensors (referred as oxygen sensors) to control emissions based on feedback of the oxygen sensors. As shown in fig. 2 and 3, the ECU 200 controls fuelling in the internal combustion (IC) engine 101 (herein after can be referred as engine 101) based on fuel feedback value received from a front oxygen sensor 103 and a rear oxygen sensor 104. After combustion, the engine 101 releases exhaust gases 106 that comprises carbon monoxide (CO), Total Hydrocarbons (THC), nitro oxide (NOx) and other pollutants. A catalytic converter 107 is provided in exhaust gas system to treat the emissions and convert the pollutants in acceptable form. The front oxygen sensor 103 is positioned before the catalytic converter 107 and the rear oxygen sensor 104 is positioned after the catalytic converter 107 in the exhaust gas system. The front oxygen sensor 103 detects the oxygen content in the exhaust gas 106 coming from the engine 101 and gives output signal 103a to the ECU 200. After treatment of the emissions, the rear oxygen sensor 104 determines the oxygen content in the treated emissions after the catalytic converter 107 and compares the determine oxygen content with the threshold value of the oxygen content on which the rear oxygen sensor 104 is calibrated. Upon comparison, the rear oxygen sensor 104 signal provides fuel feedback value 104a to the ECU 200.
[0050] The front oxygen sensor 103 and the rear oxygen sensor 104 determines the oxygen content in the exhaust gas and provides their output in term of voltages to the engine control unit for controlling the further fuelling.
[0051] The ECU 200 combines both the fuel feedback values 103a and 104a and calculates a final fuel feedback value 105 to determine air-fuel mixture in the engine 101. The ECU 200 controls fuel injectors 102 to maintain the air-fuel ratio at stoichiometric level, in the present system, air-fuel ratio is maintained more towards the lean side for better fuel mileage. Based on the final fuel feedback value 105, the ECU 200 determines whether emissions are on leaner side or on richer side. Based on the determination, fuelling is updated towards rich side or in lean side.
[0052] As shown in fig. 1, the ECU 200 is coupled with catalytic converter 107 (catalyst), front oxygen sensor 103, rear oxygen sensor 104, a plurality of injectors 102, engine 101. The ECU 200 also determines and checks health of each coupled component to ensure that all components are working fine and there is no other reason for misfiring in the engine. When there is no malfunction detected in the coupled components, the ECU 200 works on the present subject matter to make the air-fuel mixture ratio rich to avoid misfiring and generation of NOx in the emissions.
[0053] Upon detection of the misfiring in the engine, the present subject matter calculates the total fuel compensation required for avoiding the misfiring and simultaneously maintain the emissions to avoid damage and aging of the catalytic converter. In the present subject matter, total fuel compensation X amount is being compensated by three controls-front oxygen sensor, rear oxygen sensor and fuel cut revival rate.
[0054] Referring to fig. 1, the present subject matter provides is implemented in the Electronic Control Unit (ECU) 200 of the vehicle to control the emissions during misfiring in the dual fuel vehicles or single fuel vehicle having high fuel efficiency. In another embodiment, the present subject matter can be provided as separate or standalone micro-controller to work in tandem with ECU 200. The ECU 200 includes a processor(s) 202, an interface(s) 204, and a memory 206.
[0055] The processor(s) 202 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, logic circuitries, and/or any devices that manipulate data based on operational instructions.
[0056] Among other capabilities, the one or more processor(s) 202 are configured to fetch and execute computer-readable instructions and one or more routines stored in the memory 206. The memory 206 may store one or more computer-readable instructions or routines, which may be fetched and executed to implement updating target operating voltage (Vopt) and target detection time of the front oxygen sensor 103 and the oxygen sensor 104 and other operating conditions of the oxygen sensors 103, 104. The memory 206 may include any non-transitory storage device including, for example, volatile memory, such as RAM, or non-volatile memory such as EPROM, flash memory, and the like.
[0057] The interface(s) 204 may include a variety of interfaces, for example, interfaces for data input and output devices referred to as I/O devices, storage devices, various sensors, such as front oxygen sensor 103 and rear oxygen sensor 104, and plurality of fuel injector or the like. The interface(s) 204 may facilitate communication of the ECU 200 with various devices, such as fuel injectors, oxygen sensors. The interface(s) 204 may also provide a communication pathway for one or more components of the ECU 200. Examples of such components include, but are not limited to, processing unit(s) 208 and data 210.
[0058] The processing units(s) 208 may be implemented as a combination of hardware and programming (for example, programmable instructions) to implement one or more functionalities of the processing unit(s) 208. In examples described herein, such combinations of hardware and programming may be implemented in several different ways. For example, the programming for the processing unit(s) 208 may be processor-executable instructions stored on a non-transitory machine-readable storage medium and the hardware for the processing unit(s) 208 may include a processing resource (for example, one or more processors), to execute such instructions. In the present examples, the machine-readable storage medium may store instructions that, when executed by the processing resource, implement the processing unit(s) 208. In such examples, the ECU 200 may include the machine-readable storage medium storing the instructions and the processing resource to execute the instructions or the machine-readable storage medium may be separate but accessible to the ECU 200 and the processing resource. In other examples, the processing unit(s) 208 may be implemented by electronic circuitry or processing circuitry.
[0059] In an aspect, the processing unit(s) 208 may include a misfiring determining unit 212, a front oxygen sensor control unit 214, rear oxygen sensor control unit 216, fuel cut revival control unit 218, and air-fuel mixture ratio control unit 220. The processing unit(s) 208 may include other unit(s) which may implement functionalities that supplement applications or functions performed by the ECU 200.
[0060] Further, the data 210 may include data that is either stored or generated as a result of functionalities implemented by any of the components of the processing unit(s) 208. In some aspects, the data 210 may be stored in the memory 206 in the form of various data structures.
[0061] First Embodiment:
[0062] In the present subject matter, a lookup table having misfiring percentage (%) values of the engine 101 and corresponding target operating voltage (Vopt) of the front oxygen sensor and target detection time of rich or lean air-fuel mixture ratio. The lookup table is stored in the data 210 or in the memory 206. Additionally, data 210 can be organized using data models, such as relational or hierarchical data models. The data 210 may store data, including temporary data and temporary files, generated by the processing unit(s) 208 for performing the various functions of the ECU 200.
[0063] The misfiring percentage values of the engine 101 and corresponding target operating voltage (Vopt) and target detection time for the front oxygen sensor is stored in the lookup table are experimented values which is used by the ECU 200 to run the engine towards rich air-fuel mixture ration during misfiring event to avoid generation of NOx emissions and to provide power to the engine. Exemplary Look-up table is given below for reference:
Table 1
Mis-firing percentage <2% >=2% & <6% >=6% & <9% >=9% & <12% >12%
Target Operating Voltage (Vopt) in voltage X X+a X+b X+c X+d
Target Detection time for Rich and lean in Mili-second Y Y+x Y+y Y+z Y+z1

[0064] The above mentioned values are given for reference only actual values may differ from the given values. In the target operating voltage (Vopt), target operating voltage is increase by some value based on the experimented results to achieve the air-fuel ration towards rich side during an event of misfiring to avoid power loss and to avoid generation of NOx. The above mentioned addition of voltage and time detection may be referred as correction measures taken by the ECU to make the fuelling system towards the rich side.
[0065] In operation, when misfiring is happening in the engine 101, the misfiring determining unit 212 of the ECU 200 determines misfiring percentage of the engine 101. The misfiring in the engine 101 can be detected by means of Engine RPM, torque dip and any other known technology or means or parameter. The misfiring determining unit 212 determines the percentage of misfiring in the engine 101 and gives the determined percentage value to the front oxygen sensor control unit 214.
[0066] The front oxygen sensor control unit 214 compares the determined misfiring percentage of the engine 101 with the pre-stored misfiring percentage values in the lookup table. Upon comparison, the front oxygen sensor control unit 214 selects the target detection time corresponding to determined misfiring percentage of the engine 101. The front oxygen sensor control unit 214 updates the target detection time of the front oxygen sensor 103 for further detection of rich or lean of air-fuel mixture ratio based on the updated target detection time.
[0067] Example Case I: When engine misfiring percentage 4% and target detection time is being delayed by Y+b m-second based on the present subject matter by the front oxygen sensor control unit 214 by referring the lookup table.
[0068] Based on the comparison, the front oxygen sensor control unit 214 selects the target detection time Y+x m-second for the front oxygen sensor 103 and calibrates the front oxygen sensor 103 with the selected target detection time for operation. The front oxygen sensor 103 determines the oxygen content in terms of voltage in the emissions during lean and rich air fuel mixture ration with delayed detection. Referring to fig. 3, the detection of richness and leanness on rich and lean side is being delayed by ‘x’ m-second, due to which rich air-fuel mixture ratio is achieved to avoid generation of NOx during misfiring event and to generate power. Based on the delayed detection of rich or lean, the air fuel mixture ration control unit 216 corrects the air-fuel ratio towards richer side.
For example:
Mis-firing percentage 4%
Target detection time = Y+x msec, where b is 10 msec
Determined detection time = Y+10msec
[0069] Example Case II: When engine misfiring percentage 7% and target operating voltage of front O2 sensor is being increased to X+b volts based on the present subject matter by the front oxygen sensor control unit 214 by referring the lookup table.
[0070] Based on the comparison, the front oxygen sensor control unit 214 selects the target operating voltage (Vopt) X+b volts for the front oxygen sensor 103 and calibrates the front oxygen sensor 103 with the selected target detection time for operation. The front oxygen sensor 103 determines the oxygen content in terms of voltage in the emissions during lean and rich air fuel mixture ratio. Based on the comparison, the front oxygen sensor control unit 214 increases target operating voltage by ‘b’ to change the air-fuel mixture ratio towards the richer side to avoid generation of NOx during misfiring event and to generate power. Based on the increased target operating voltage of the front oxygen sensor 103, the air fuel mixture ration control unit 216 corrects the air-fuel ratio towards richer side based on the inputs received from the front oxygen sensor 103 with increased target operating voltage (Vopt).
For example:
Mis-firing percentage 7%
Target detection Voltage = X+b volts, where b is volts
Determined operating voltage = X+b V
Increased target voltage = .10 V
[0071] The air-fuel mixture ratio control unit 220 adds additional voltage as fuel feedback value to determine the air-fuel ratio more towards the richer side. With the updated target operating voltage (Vopt), the front oxygen sensor 103 determines oxygen content in the emissions 106a and compares the same with the increased target voltage. With the increase of target operating voltage of the front oxygen sensor 103, the air-fuel mixture ratio control unit 216 receives more fuel feedback value based on actual content of oxygen in the emissions to control the air-fuel mixture ratio to avoid generation of NOx. Resultantly, the air-fuel ratio is maintained to avoid generation of NOx during misfiring event and to provide required power to the engine.
[0072] The air fuel mixture ratio control unit 220 receives fuel feedback value of the front oxygen sensor 103 to control the air-fuel ratio toward richer side. With implementation of the present subject matter of the first embodiment, the air fuel mixture ratio control unit 220 receives fuel feedback value based on the updated target operating voltage (Vopt) and/or detection time delay to improve emission performance by reducing NOx generation during misfiring event.
[0073] The ECU 200 increases the target detection time and/or target operating voltage (Vopt) only when there is no malfunction has been detected by the ECU 200 with respect to front, rear oxygen sensor, fuel injectors, catalytic converter, engine, and catalytic converter warm up event has also completed.
[0074] FIG. 4 illustrates a method 400 for improving emissions by increasing detection time delay and increasing target operating voltage (Vopt) of the front oxygen sensor during misfiring event in the engine 101. The order in which the method 400 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any appropriate order to carry out the method 400 or an alternative method. Additionally, individual blocks may be deleted from the method 400 without departing from the scope of the subject matter described herein.
[0075] At step 402, the method includes determining misfiring percentage of the internal combustion engine. The misfiring percentage can be determined by the existing technologies based on the engine RPM and drop in torque and any other known technology.
[0076] At step 404, the method includes comparing the determined misfiring percentage of the internal combustion engine with a pre-stored lookup table having predetermined experimented values for misfiring percentage of the internal combustion engine and corresponding target detection time of a front oxygen sensor to detect the air-fuel mixture is rich or lean based on the center voltage or operating voltage.
[0077] At step 406, the method includes selecting the target detection time of the front oxygen sensor 103 from the pre-stored lookup table.
[0078] At step 408, the method includes updating and calibrating the target detection time of the front oxygen sensor 103 dynamically based on the selected target detection time from the pre-stored lookup table.
[0079] In another embodiment, at step 410, the present method includes comparing the determined misfiring percentage of the internal combustion engine 101 with a pre-stored lookup table having predetermined experimented values for misfiring percentage of the internal combustion engine 101 and corresponding target operating voltage (Vopt) or centre operating voltage of the front oxygen sensor 103 to detect the air-fuel mixture is rich or lean.
[0080] At step 412, the method includes selecting the target operating voltage (Vopt) of the front oxygen sensor 103 from the pre-stored lookup table.
[0081] At step 414, the method includes updating and calibrating the target operating voltage (Vopt) of the front oxygen sensor 103 dynamically based on the selected target operating voltage (Vopt) from the pre-stored lookup table.
[0082] Upon updating and calibrating the target operating voltage (Vopt) or central operating voltage of the front oxygen sensor 103, the air fuel mixture ratio control unit 220 to change the stoichiometry target to richer side in order to achieve the richness to avoid NOx generation during misfiring event.
[0083] Second Embodiment
[0084] In the present subject matter, data 210 has a lookup table having misfiring percentage (%) values of the engine 101 and corresponding target operating voltage (Vopt) of the rear oxygen sensor of rich or lean air-fuel mixture ratio. The lookup table is stored in the data 210 or in the memory 206. Additionally, the data 210 can be organized using data models, such as relational or hierarchical data models. The data 210 may store data, including temporary data and temporary files, generated by the processing unit(s) 208 for performing the various functions of the ECU 200.
[0085] The misfiring percentage values of the engine 101 and corresponding target operating voltage (Vopt) for the rear oxygen sensor is stored in the lookup table are experimented values which is used by the ECU 200 to run the engine towards rich air-fuel mixture ratio during misfiring event to avoid generation of NOx emissions and to provide required power to the engine. Exemplary Look-up table is given below for reference:

Table 1
Mis-firing percentage <2% >=2% & <6% >=6% & <9% >=9% & <12% >12%
Target Operating Voltage (Vopt) in voltage X X+a X+b X+c X+d

[0086] The above mentioned values are given for reference only actual values may differ from the given values. In the target operating voltage (Vopt) or central operating voltage, the target operating voltage (Vopt) increase by some value based on the experimented results to achieve the air-fuel ratio towards rich side during an event of misfiring to avoid power loss and to avoid generation of NOx. The above mentioned addition of voltage may be referred as correction measures or compensation measures taken by the ECU to make the fuelling system towards the rich side. The compensation calculated by the ECU to avoid misfiring is distributed in the present embodiment by changing target operating voltage (Vopt).
[0087] In operation, when misfiring is happening in the engine 101, the misfiring determining unit 212 of the ECU 200 determines misfiring percentage of the engine 101. The misfiring in the engine 101 can be detected by means of Engine RPM, torque dip and any other known technology or means or parameters. The misfiring determining unit 212 determine the percentage of misfiring in the engine 101 and gives the determined percentage value to the rear oxygen sensor control unit 216.
[0088] The rear oxygen sensor control unit 216 compares the determined misfiring percentage of the engine 101 with the pre-stored misfiring percentage values in the lookup table.
[0089] Example Case I: When engine misfiring percentage 7% and target operating voltage is being increased to X+b volts based on the present subject matter by the rear oxygen sensor control unit 214 by referring the lookup table.
[0090] Based on the comparison, the rear oxygen sensor control unit 214 selects the target operating voltage (Vopt) X+b volts for the rear oxygen sensor 104 and calibrates the rear oxygen sensor 104 with the selected target operating voltage (Vopt) for operation. The rear oxygen sensor 104 determines the oxygen content in terms of voltage in the emissions during lean and rich air fuel mixture ratio. Based on the comparison, the rear oxygen sensor control unit 214 increases target operating voltage by ‘b’ to change the air-fuel mixture ratio towards the richer side to avoid generation of NOx during misfiring event and to generate required power. Based on the increased target operating voltage (Vopt) of the rear oxygen sensor 104, the air fuel mixture ratio control unit 220 corrects the air-fuel ratio towards richer side based on the inputs received from the rear oxygen sensor 104 with increased target operating voltage (Vopt).
For example:
Mis-firing percentage 7%
Target detection time = X+b volts, where b is .10 volt
Determined operating voltage = X+.10V
Increased target voltage = .10 V
[0091] The air-fuel mixture ratio control unit 220 adds additional voltage as fuel feedback value to determine the air-fuel ratio more towards the richer side. With the updated target operating voltage (Vopt), the rear oxygen sensor 104 determines oxygen content in the emissions 106a and compares the same with the increased feedback target operating voltage. With the increase of target operating voltage of the rear oxygen sensor 104, the air-fuel mixture ratio control unit 216 receives more fuel feedback value based on actual content of oxygen in the emissions to control the air-fuel mixture ratio to avoid generation of NOx. Resultantly, the air-fuel ratio is maintained to avoid generation of NOx during misfiring event and to provide required power to the engine.
[0092] The air fuel mixture ratio control unit 220 receives fuel feedback value of the rear oxygen sensor 103 to control the air-fuel ratio toward richer side. With implementation of the present subject matter, the air fuel mixture ratio control unit 220 receives fuel feedback value based on the updated target operating voltage (Vopt) to improve emission performance by reducing NOx generation during misfiring event.
[0093] The ECU 200 increases the target operating voltage (Vopt) only when there is no malfunction has been detected by the ECU 200 with respect to front, rear oxygen sensor, fuel injectors, catalytic converter, engine, and catalytic converter warm up event has also completed.
[0094] FIG. 5 illustrates a method 500 for improving emissions increasing target operating voltage (Vopt) of the rear oxygen sensor 104 during misfiring event in the engine 101. The order in which the method 500 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any appropriate order to carry out the method 500 or an alternative method. Additionally, individual blocks may be deleted from the method 500 without departing from the scope of the subject matter described herein.
[0095] At step 502, the method includes determining misfiring percentage of the internal combustion engine. The misfiring percentage can be determined by the existing technologies based on the engine RPM and/or drop in torque and any other known technology.
[0096] At step 504, the method includes comparing the determined misfiring percentage of the internal combustion engine with a pre-stored lookup table having predetermined experimented values for misfiring percentage of the internal combustion engine and corresponding target operating voltage (Vopt) of the rear oxygen sensor 104 to detect the air-fuel mixture is rich.
[0097] At step 506, the method includes selecting the target operating voltage (Vopt) of the rear oxygen sensor 104 from the pre-stored lookup table.
[0098] At step 508, the method includes updating and calibrating the target operating voltage (Vopt) of the rear oxygen sensor 104 dynamically based on the selected target operating voltage (Vopt) from the pre-stored lookup table.
[0099] Upon updating and calibrating the target operating voltage (Vopt) the rear oxygen sensor 104, the air fuel mixture ratio control unit 220 to change the stoichiometry target to richer side in order to achieve the richness to avoid NOx generation during misfiring event.
[00100] Third Embodiment:
[00101] In the present subject matter, a lookup table having misfiring percentage (%) values of the engine 101 during fuel cut and fuel cut revival event and corresponding target air-fuel ratio and target time duration for running the engine 101 on the target air-fuel ratio. The lookup table is stored in the data 210 or in the memory 206. Additionally, data 210 can be organized using data models, such as relational or hierarchical data models. The data 210 may store data, including temporary data and temporary files, generated by the processing unit(s) 208 for performing the various functions of the ECU 200.
[00102] The misfiring percentage values of the engine 101 and corresponding target air-fuel ratio and target time duration is stored in the lookup table as experimented values to be used by the ECU 200 to run the engine towards a richer side during misfiring event to avoid generation of NOx emissions and to provide power to the engine at the event of fuel cut and fuel cut revival. Exemplary Look-up table is given below for reference:
Table 1
Mis-firing percentage at fuel cut and fuel cut revival event <2% >=2% & <6% >=6% & <9% >=9% & <12% >12%
Target air- Fuel ratio X X+a X+b X+c X+d
Target time duration Y Y+A Y+B Y+C Y+D

[00103] For example, during the fuel cut and fuel cut revival event, the ECU determines misfiring percentage is 4%, by referring the pre-stored look up table, the ECU 200 determines target air-fuel ratio be X+a and target time duration for target air-fuel ratio be Y+A. The ECU 200 increases the air-fuel ratio to target air-fuel ratio for the selected target time duration to run the engine more towards the richer side to avoid generation of NOx and keep the fuelling in closed loop which is within boundaries to maintain the fuel efficiency.
[00104] The above mentioned values are given for reference only actual values may differ from the given values. As shown in the look up table, the target air-fuel ratio is increased by some value based on the experimented results to achieve the fuel cut revival enrichment amount towards rich side during an event of misfiring to avoid power loss and to avoid generation of NOx. The above mentioned addition of amount of fuel may be referred as correction measures taken by the ECU to make the fuelling system towards the rich side. Further, the ECU 200, based on the lookup table, decides the time duration for the correction in the air-fuel ratio to run the engine on richer side to avoid generation of NOx.
[00105] In operation, when misfiring is happening in the engine 101, the misfiring determining unit 212 of the ECU 200 determines misfiring percentage of the engine 101. The misfiring in the engine 101 can be detected by means of Engine RPM, torque dip, and any other known technology. During an event of fuel cut and fuel cut revival, the misfiring determining unit 212 determine the percentage of misfiring in the engine 101 and gives the determined percentage value to the fuel cut revival control unit 218.
[00106] The fuel cut revival control unit 218 compares the determined misfiring percentage of the engine 101 with the pre-stored misfiring percentage values in the lookup table. Upon comparison, the fuel cut revival control unit 218 selects the target air-fuel ratio and target duration time corresponding to determined misfiring percentage of the engine 101. The fuel cut revival control unit 218 updates the target air-fuel ratio and target duration time for enriched air fuel mixture to run the engine 101 on richer side based on the updated target air-fuel ration for predetermined target time duration.
[00107] The air-fuel mixture ratio control unit 220 receives fuel feedback value from the fuel cut revival control unit 218 to control air-fuel mixture according to target air-fuel ratio and target time duration for the selected target air-fuel ratio in the engine towards richer side. With implementation of the present subject matter, the air-fuel mixture control unit 220 receives fuel feedback value or correction value with target time duration based on the lookup table to improve emission performance by reducing NOx generation during misfiring event.
[00108] The air-fuel mixture control unit 220 adds additional amount of fuel as fuel feedback value or correction value to shift the air-fuel ratio to target air-fuel ration which is more towards the richer side. Upon running on the engine on the target air-fuel ratio for determined target time duration, the ECU 200 activates other system to control the closed loop of fuelling based on the fuel feedback value of the front oxygen sensor 103 and the rear oxygen sensor 104. Resultantly, during the fuel cut and fuel cut revival event, the target air-fuel ratio is maintained for target time duration to avoid generation of NOx during misfiring event and to provide required power to the engine.
[00109] FIG. 6 illustrates a method 600 for improving emissions by controlling target air-fuel ratio and target time duration for the target air-fuel ratio to make the air-fuel ratio towards the richer side during misfiring event in the engine 101. The order in which the method 600 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any appropriate order to carry out the method 600 or an alternative method. Additionally, individual blocks may be deleted from the method 600 without departing from the scope of the subject matter described herein.
[00110] At step 602, the method includes determining misfiring percentage of the internal combustion engine during an event of fuel cut and fuel cut revival. The misfiring percentage can be determined by the existing technologies based on the engine RPM and/or drop in torque and any other known technology.
[00111] In an embodiment, at step 604, the method includes comparing the determined misfiring percentage of the internal combustion engine 101 with a pre-stored lookup table having predetermined experimented values for misfiring percentage of the internal combustion engine 101 and corresponding target air-fuel ration and target time duration for the target air-fuel ratio to run the engine in richer side to avoid generation of NOx.
[00112] At step 606, the method includes selecting the target air-fuel ratio and target time duration from the pre-stored lookup table.
[00113] At step 608, the method includes updating and calibrating the target air-fuel ratio and target time duration dynamically based on the selected target air-fuel ratio and target time duration from the pre-stored lookup table to run the engine towards richer side to avoid generation of NOx.
[00114] Upon updating and calibrating the target air-fuel ratio and the target time duration, the air-fuel mixture control unit 220 changes the air fuel mixture ratio towards the richer side in order to achieve the targeted richness and to avoid NOx generation during misfiring event.
[00115]
Technical advantages:
[00116] With the first embodiment of present system implemented in the Engine Control Unit (ECU) a rich air-fuel mixture is achieved to improve emission performance by controlling target operating voltage (Vopt) of the front oxygen sensor during misfiring event.
[00117] With the second embodiment of present system implemented in the Engine Control Unit (ECU) a rich air-fuel mixture is achieved to improve emission performance by controlling target operating voltage (Vopt) of the rear oxygen sensor during misfiring event.
[00118] With the third embodiment of present system implemented in the Engine Control Unit (ECU) a rich air-fuel ratio is achieved to improve emission performance during misfiring event and maintain the fuel efficiency to control the air fuel ratio in closed loop.
[00119] With the present disclosure, there is no need to add any extra component in the system to improve the emission performance.
[00120] With the present system, there is no requirement of any other new hardware, existing hardware can be optimized to obtain technical advanced results.
[00121] With the present system, the existing hardware works in more efficient and technically advance way to reduce the emissions.
[00122] It should be understood, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, as apparent from the discussion herein, it is appreciated that throughout the description, discussions utilizing terms such as “receiving,” or “determining,” or “retrieving,” or “controlling,” or “comparing,” or the like, refer to the action and processes of an electronic control unit, or similar electronic device, that manipulates and transforms data represented as physical (electronic) quantities within the control unit’s registers and memories into other data similarly represented as physical quantities within the control unit memories or registers or other such information storage, transmission or display devices.
[00123] Further, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[00124] It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
[00125] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.