FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13]
TITLE: “A SYSTEM FOR ESTIMATING INTAKE AIR-FLOW OF AN INTERNAL COMBUSTION ENGINE AND A METHOD THEREOF”
Name and Address of the Applicant:
TATA MOTORS LIMITED; an Indian company having a registered address at Bombay
House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India.
Nationality: Indian
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
Present disclosure, in general, relates to a field of automobiles. Particularly, but not exclusively, the present disclosure relates to an internal combustion engine of a vehicle. Further, embodiments of the present disclosure relate to a system and method for estimating intake air¬flow for the internal combustion engine.
BACKGROUND OF THE DISCLOSURE
Many vehicles in operation are powered by internal combustion (IC) engines. A vehicle, such as a passenger vehicle and or commercial vehicle, being powered by the internal combustion engine may require control of various operations such as, but not limited to, fuel intake, air intake, exhaust of gases from an engine, and the like for efficient performance of the internal combustion engine. Air is typically delivered into a combustion chamber of the internal combustion engine from an intake manifold. A throttle valve regulates delivery of air from an outside environment into the intake manifold. As is well known, opening a throttle valve causes air to enter the intake manifold and closing the throttle valve restricts flow of air into the internal combustion engine.
Measurement of intake air flow is used for controlling various functions of the internal combustion engine, such as efficient combustion, exhaust gas recirculation (EGR), selective catalytic reduction (SCR), diesel particulate filtering (DPF), on-board diagnostics (OBD), and other engine combustion operations. Conventionally, a sensor, such as, but not limited to, a hot wire anemometer, a pressure flow module, or a differential pressure-based air sensor, is used for measurement of value of intake air-flow. Usage of such sensors increases cost and complexity of the vehicles. Further, installation of such sensors is difficult and requires frequent servicing or replacement.
The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the conventional mechanisms.
SUMMARY OF THE DISCLOSURE
One or more shortcomings of the prior art are overcome by a method and a system as claimed and additional advantages are provided through the method and the system as claimed in the present disclosure. Additional features and advantages are realized through the techniques of

the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
In one non-limiting embodiment of the present disclosure a method for estimating intake air-flow of an internal combustion engine is disclosed. The method includes steps of receiving by a control unit, oxygen concentration value in an exhaust gas. The control unit receives a plurality of combustion parameters of the internal combustion engine corresponding to operation of a fuel injector. The control unit then estimates the intake air-flow based on at least one of the oxygen concentration value and the plurality of combustion parameters.
In an embodiment, the method includes comparing, by the control unit, at least two combustion parameters with at least two combustion threshold values corresponding to the at least two combustion parameters. The control unit estimates the intake air-flow based on the oxygen concentration value when the at least two combustion parameters of the plurality of combustion parameters are greater than the at least two combustion threshold values.
In an embodiment, the control unit determines the intake air-flow based on the plurality of combustion parameters of the internal combustion engine when the at least two combustion parameters of the internal combustion engine are less than the at least two combustion threshold values.
In an embodiment, the at least two combustion parameters of the internal combustion engine comprises a speed of the internal combustion engine and a fuel intake of the internal combustion engine.
In an embodiment, the control unit determines the oxygen concentration value based on a plurality of exhaust parameters comprising at least one of: NOx concentration value, and CO2 concentration value in the exhaust gas.
In an embodiment, the plurality of combustion parameters comprises at least one of exhaust gas temperature, exhaust gas pressure, volumetric efficiency of the internal combustion engine, Exhaust Gas Recirculation (EGR) valve position, an accelerator pedal position, and engine speed.
In another non-limiting embodiment, a method for estimating intake air-flow of an internal combustion engine is disclosed. The method includes receiving, by a control unit, NOx

concentration value from an exhaust gas of the internal combustion engine. The control unit determines oxygen concentration value in the exhaust gas from the internal combustion engine based on the NOx concentration value from the exhaust gas. Finally, the control unit estimates the intake air-flow based on the determined oxygen concentration value from the exhaust gas.
In an embodiment, the control unit receives at least one of NOx concentration value and CO2 concentration value in the exhaust gas.
In an embodiment, the control unit determines the oxygen concentration value based on the CO2 concentration value.
In another non-limiting embodiment, a method for estimating intake air-flow of an internal combustion engine based on operation of a fuel injector is disclosed. The method includes steps of receiving, by a control unit, a plurality of combustion parameters of the internal combustion engine corresponding to operation of the fuel injector. The control unit is configured to estimate the intake air-flow based on the plurality of combustion parameters of the internal combustion engine corresponding to operation of the fuel injector.
In another non-limiting embodiment, a system for estimating intake air-flow of an internal combustion engine is disclosed. The system comprises one or more first sensors, one or more second sensors and a control unit. The one or more first sensors are configured to detect and transmit oxygen concentration value in an exhaust gas of the internal combustion engine. The one or more second sensors configured to detect and transmit a plurality of combustion parameters corresponding to operation of a fuel injector. The control unit is communicatively coupled to the one or more first sensors and the one or more second sensors. The control unit is configured to receive the oxygen concentration value from the exhaust gas sensed by the one or more first sensors. The control unit receives the plurality of combustion parameters of the internal combustion engine from the one or more second sensors corresponding to operation of the fuel injector. Lastly, the control unit estimates the intake air-flow based on at least one of the oxygen concentration value and the plurality of combustion parameters.
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 ACCOMPANYING DRAWINGS
The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
Figure 1 is an exemplary block diagram of a system for estimating an intake air-flow of an internal combustion engine, in accordance with an embodiment of the present disclosure.
Figure 2 is a flow diagram depicting a method for estimating the intake air-flow of the internal combustion engine, in accordance with an embodiment of the present disclosure.
Figure 3 is a flow diagram depicting a method for estimating the intake air-flow of the internal combustion engine based on NOx concentration in an exhaust of the internal combustion engine, in accordance with an embodiment of the present disclosure.
Figure 4 is a flow diagram depicting a method for estimating the intake air-flow of the internal combustion engine based on operation of a fuel injector of the internal combustion engine, in accordance with an embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system and method illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, assembly, mechanism, system, method that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device or method. In other words, one or more elements in a system proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or method.
Embodiments of the present disclosure a method for estimating intake air-flow of an internal combustion engine. The method includes steps of receiving by a control unit oxygen concentration value in an exhaust gas sensed by one or more first sensors. The control unit receives a plurality of combustion parameters of the internal combustion engine from one or more second sensors corresponding to operation of a fuel injector. The control unit estimates the intake air-flow based on at least one of the oxygen concentration value and the plurality of combustion parameters. With such configuration, the method eliminates need for a dedicated sensor for measurement of intake air-flow. Further, the method may provide substantially uninterrupted intake air-flow measurement for the internal combustion engine, thereby resulting in efficient performance of the internal combustion engine. Elimination of such sensors reduces cost and complexity of the vehicles.
The disclosure is described in the following paragraphs with reference to Figures 1 to 4. In the figures, the same element or elements which have same functions are indicated by the same reference signs. It is to be noted that, the vehicle is not illustrated in the figures for the purpose of simplicity. One skilled in the art would appreciate that the system and the method as disclosed in the present disclosure may be used in any vehicle including but not liming to heavy and light commercial vehicles, load carrying vehicles, passenger vehicles, and the like. The system and the method of the present disclosure may also be implemented in vehicles having internal combustion engine without deviating from the principles of the present disclosure.
Figure 1 illustrates a block diagram of a system (100) for estimating intake air-flow of an internal combustion engine (12) in a vehicle [not explicitly shown in figures]. The system (100) may include one or more first sensors (1) configured to detect and/or transmit oxygen concentration value in an exhaust gas of the internal combustion engine (12). The one or more first sensors (1) may include at least one of a NOx sensor (5) and a CO2 sensor (6) positioned in an exhaust manifold [not shown in figures] of the internal combustion engine (12).

The system (100) may also include one or more second sensors (2) configured to detect a plurality of combustion parameters corresponding to operation of a fuel injector (3) of the internal combustion engine (12). The one or more second sensors (2) may transmit a plurality of signals corresponding to the plurality of combustion parameters upon detection. The plurality of combustion parameters may be including at least one of exhaust gas temperature, an exhaust gas pressure, a volumetric efficiency of the internal combustion engine (12), an exhaust gas recirculation valve position, an accelerator pedal position, engine speed and combination thereof.
In an embodiment, the one or more second sensors (2) may include at least one temperature sensor (7) positioned in a coolant circuit of the internal combustion engine (12), at least one pressure sensor (8) positioned in a manifold of the internal combustion engine (12), an Exhaust Gas Recirculation (EGR) valve sensor (9), an accelerator pedal position sensor (13) and a speed sensor (10). In an embodiment, the accelerator pedal position sensor (13) may be integrated to the accelerator pedal or may be removably attached to the accelerator pedal. The speed sensor (10) may be configured to detect at least one of speed of the vehicle and speed of the internal combustion engine (12).
Further, the system (100) may include a control unit (4) communicatively coupled to the one or more first sensors (1) and the one or more second sensors (2) configured to receive at least one of the oxygen concentration value and the plurality of combustion parameters of the internal combustion engine (12) from the one or more first sensors (1) and the one or more second sensors (2) respectively. The control unit (4) may receive the oxygen concentration value from the exhaust gas of the internal combustion engine (12) from the one or more first sensors (1) to estimate the intake air-flow of the internal combustion engine (12) based on the oxygen concentration value. The control unit (4) may receive the plurality of combustion parameters from the one or more second sensors (2) corresponding to operation of the fuel injector (3) to estimate the intake air-flow of the internal combustion engine (12) based on the plurality of combustion parameters. In an embodiment, the control unit (4) may be communicatively coupled to an engine control module (11), which may be communicatively coupled to the one or more first sensors (1) and the one or more second sensors (2) as can be seen in Figure 1.

In an embodiment, the control unit (4) may estimate the intake air-flow of the internal combustion engine (12) based on the oxygen concentration value, the plurality of combustion parameters, or both. The control unit (4) may compare at least two combustion parameters of the internal combustion engine (12) with at least two combustion threshold values corresponding to the at least two combustion parameters. For the sake of explanation, the at least two combustion parameters are illustrated as fuel intake value from a fuel injector (3) of the internal combustion engine (12) and speed of the internal combustion engine (12). However, similar other combustion parameters of the internal combustion engine (12) may also be taken as the at least two combustion parameters based on certain conditions that will be selected by the control unit such as, but not limited to, ambient pressure, boost pressure and fuel pressure.
In an embodiment, the at least two combustion threshold values may include a threshold fuel intake value ranging from 0 mg/stk to 150 mg/stk and threshold speed of the internal combustion engine (12) ranging from 600 to 1500 rpm based on the type of vehicle. For example, the threshold speed of the internal combustion engine (12) for a passenger vehicle may be ranging from 600 rpm to 5500 rpm, whereas the threshold speed of the internal combustion engine (12) for a commercial vehicle may be ranging from 600 rpm to 4000 rpm.
The control unit (4) may determine the intake air-flow of the internal combustion engine (12) based on the oxygen concentration value when the at least two combustion parameters of the internal combustion engine (12) may be greater than the at least two combustion threshold values i.e., for instance, when the speed of the internal combustion engine (12) is greater than the threshold speed and the fuel intake value is greater than the threshold fuel intake value. For example, the control unit (4) may determine the intake air-flow of the internal combustion engine (12) based on the oxygen concentration value, when the vehicle may be accelerating and correspondingly fuel in the vehicle being consumed and combusted for generation of power to propel the vehicle. As an exemplary embodiment, Table 1 below illustrates oxygen concentration as a function of fuel being consumed by the internal combustion engine for determining inlet air-flow into the internal combustion engine.
Referring now to Table 1, which illustrates correlation between the oxygen concentration value and fuel intake of the internal combustion engine (12). The control unit (4) may determine the intake air-flow of the internal combustion engine (12) based on the oxygen concentration value with fuel intake value of the internal combustion engine (12). For example, the control unit (4)

may receive oxygen concentration value as 15 from at least one of the at least one CO2 sensor (6) and the at least one NOx sensor (5) and may receive fuel intake value as 40 and the control unit (4) may determine the intake air-flow corresponding to the oxygen concentration value and the fuel intake value as a first preliminary intake air-flow.
Table 1:

Oxygen %
0 5 8 10 12 15 17 19 21
Fuel 0
5
10
20
40
60
80
90
100
Referring now to table 2, which illustrates correlation between speed and the fuel intake value of the internal combustion engine (12) and aids in determining the intake air-flow when the internal combustion engine may be starting and other such conditions where the first preliminary intake air-flow determined by the control unit (4) based on the oxygen concentration value and the fuel intake may be less accurate. The control unit (4) may determine a first correction factor for the intake air-flow based on the speed of the internal combustion engine with the fuel intake. The control unit may multiply the first correction factor with the first preliminary intake air-flow obtained from table 1 to obtain the intake air-flow of the internal combustion engine (12) based on the oxygen concentration value.
Table 2:

Engine Speed
0 500 800 1200 1600 2000 2300 2600 3000
Fuel 0

5
10
20
40
60
80
90
100
The control unit (4) may be configured to determine the intake air-flow of the internal combustion engine (12) based on the plurality of combustion parameters when the at least two combustion parameters may be less than the at least two combustion threshold values i.e., if the speed of the internal combustion engine (12) is less than the threshold speed and the fuel intake value is less than the threshold fuel intake value, for example, when the internal combustion engine (12) may be idling or traveling downhill. In the illustrative embodiment, the control unit (4) may be configured to determine the intake air-flow by determining volume of intake air-flow based on the temperature of the exhaust gas, pressure of the exhaust gas from the plurality of combustion parameters received from the one or more second sensors (2). The control unit (4) may be configured to determine the intake air-flow of the internal combustion engine (12) based on the plurality of combustion parameters, and not the oxygen concentration value, as it may not be possible to accurately determine the intake air-flow based on the oxygen concentration value when the fuel intake is low and/or speed of the internal combustion engine (12) is less.
When the speed and/or fuel intake of the internal combustion engine (12) are less than the threshold speed and the threshold fuel intake, the control unit may be configured to determine the intake air-flow based on the plurality of combustion parameters. Referring now to table 3, which illustrates correlation between speed and boost pressure of the internal combustion engine (12). The control unit (4) may determine the intake air-flow of the internal combustion engine (12) based on speed and boost pressure of the internal combustion engine (12). For example, the control unit (4) may receive speed as 500 RPM and may receive boost pressure value as 1000 and the control unit (4) may determine the intake air-flow corresponding to the speed and the boost pressure value as a second preliminary intake air-flow.

Table 3:

Engine Speed
0 0 500 800 1200 1600 2000 2300 2600 3000
Boost

pressure 250
500
750
1000
1500
2250
2750
3000
Referring now to Table 4, which illustrates exemplary second correction factor based on boost temperature of the internal combustion engine (12). The control unit (4) may determine a second correction factor based on boost temperature of the internal combustion engine as shown in table 4. For example, the control unit (4) may determine the second correction factor as 0.92 if the boost temperature is received as 70.
Table 4:

Boost temperature
-20 0 25 40 70 90 110 150 200
1.2 1.1 1 .97 0.92 0.85 0.8 0.75 0.65
Referring now to Table 5, which illustrates correlation between speed and EGR valve position of the internal combustion engine (12). The control unit (4) may determine a third correction factor based on speed and EGR valve position of the internal combustion engine (12) as show in table 5.
Table 5:

0 Engine 0 RPM 500 800 1200 1600 2000 2300 2600 3000

EGR 5
Valve 10
Position 20 40 60 80 90 100
Referring now to Table 6, which illustrates correlation between the EGR valve position and fuel intake of the internal combustion engine (12). The control unit (4) may determine a fourth correction factor based on fuel intake and EGR valve position of the internal combustion engine (12) as show in table 5. The control unit (4) may multiply the second preliminary intake air¬flow with the second correction factor, the third correction factor and the fourth correction factor to obtain the intake air-flow based on the plurality of combustion parameters.
Table 6:

Fuelling
0 0 10 20 30 50 70 80 90 100
EGR

Valve 5
Position 10 20 40 60 80 90 100
The control unit (4) may also be associated with other control units including, but not limited to, body control unit, engine control unit, transmission control unit, and the like. The control unit (4) may be comprised of a processing unit. The processing unit may comprise at least one data processor for executing program components for executing user- or system-generated requests. The processing unit may be a specialized processing unit such as integrated system

(bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc. The processing unit may include a microprocessor, such as AMD Athlon, Duron or Opteron, ARM’s application, embedded or secure processors, IBM PowerPC, Intel’s Core, Itanium, Xeon, Celeron or other line of processors, etc. The processing unit may be implemented using a mainframe, distributed processor, multi-core, parallel, grid, or other architectures. Some embodiments may utilize embedded technologies like application-specific integrated circuits (ASICs), digital signal processors (DSPs), Field Programmable Gate Arrays (FPGAs), etc.
The control unit (4) may be disposed in communication with one or more memory devices (e.g., RAM, ROM etc.) via a storage interface. The storage interface may connect to memory devices including, without limitation, memory drives, removable disc drives, etc., employing connection protocols such as serial advanced technology attachment (SATA), integrated drive electronics (IDE), IEEE-1394, universal serial bus (USB), fiber channel, small computing system (100) interface (SCSI), etc. The memory drives may further include a drum, magnetic disc drive, magneto-optical drive, optical drive, redundant array of independent discs (RAID), solid-state memory devices, solid-state drives, etc.
Referring now to figure 2, which is an exemplary block diagram illustrating a method (200) of estimating the intake air-flow of the internal combustion engine (12).
The method (200) may describe in the general context of the processor executable instructions in the control unit (4). Generally, the executable instructions may include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform particular functions or implement particular abstract data types.
The order in which the method (200) is described is not intended to be construed as a limitation, and any number of the described method (200) blocks may be combined in any order to implement the method (200). Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein. Furthermore, the method (200) can be implemented in any suitable hardware, software, firmware, or combination thereof.
At block 201, the control unit (4) may be configured to receive oxygen concentration value of an exhaust gas from the one or more first sensors (1) communicatively coupled to the control

unit (4). The one or more first sensors (1) may include at least one NOx sensor (5) and at least one CO2 sensor (6) communicatively coupled to the control unit (4). The method (200) estimates the intake air-flow of the internal combustion engine (12) by receiving NOx concentration value from the one or more second sensors (2) such as the at least one NOx sensor (5) and at least one CO2 sensor (6) available in the vehicle and thereby eliminates need for dedicated sensors to measure intake air-flow of the internal combustion engine (12).
At block 202, the control unit (4) may be configured to receive a plurality of combustion parameters from one or more second sensors (2) corresponding to operation of the fuel injector (3) of the internal combustion engine (12). The one or more second sensors (2) may include at least one temperature sensor (7) positioned in a coolant circuit of the internal combustion engine (12), at least one pressure sensor (8) positioned in a manifold of the internal combustion engine (12), an Exhaust Gas Recirculation (EGR) valve sensor (9), an accelerator pedal position sensor (13), a speed sensor (10) and combination thereof. In an embodiment, the accelerator pedal position sensor (13) may be integrated to the accelerator pedal or may be removably attached to the accelerator pedal. The speed sensor (10) may be configured to detect at least one of the speed of the vehicle and the speed of the internal combustion engine (12).
The control unit (4) may compare at least two combustion parameters of the internal combustion engine (12) with at least two combustion threshold values corresponding to the at least two combustion parameters. For sake of explanation, the at least two combustion parameters are illustrated as the fuel intake value from the fuel injector (3) of the internal combustion engine (12) and speed of the internal combustion engine (12) to selectively determine the intake air-flow of the internal combustion engine (12) based on at least one of the oxygen concentration value and the plurality of combustion parameters and the same shall not be considered a limitation.
In an embodiment, the at least two combustion threshold values may include a threshold fuel intake value ranging from 0 mg/stk to 150 mg/stk and threshold speed of the internal combustion engine (12) ranging from 600 to 1500 rpm based on the type of vehicle. For example, the threshold speed of the internal combustion engine (12) for a passenger vehicle may be ranging from 600 rpm to 5500 rpm, whereas the threshold speed of the internal combustion engine (12) for a commercial vehicle may be ranging from 600 rpm to 4000 rpm.

At block 203, the control unit (4) may determine the intake air-flow of the internal combustion engine (12) based on the oxygen concentration value when the at least two combustion parameters of the internal combustion engine (12) may be greater than the at least two combustion threshold values i.e., when the speed of the internal combustion engine (12) is greater than the threshold speed and the fuel intake value may be greater than the threshold fuel intake value. The control unit (4) may be configured to determine the intake air-flow of the internal combustion engine (12) based on the plurality of combustion parameters when the at least two combustion parameters may be less than the at least two combustion threshold values i.e., when the speed of the internal combustion engine (12) may be less than the threshold speed and the fuel intake value may be less than the threshold fuel intake value. In the illustrative embodiment, the control unit (4) may be configured to determine the intake air-flow by determining volume of intake air-flow based on the temperature of the exhaust gas, pressure of the exhaust gas from the plurality of combustion parameters received from the one or more second sensors (2).
Referring now to Figure 3 which is a flow diagram depicting a method (300) for estimating the intake air-flow of the internal combustion engine (12) based on NOx concentration in an exhaust of the internal combustion engine (12). At block 301, the control unit (4) may receive NOx concentration value from the one or more first sensors (1) communicatively coupled to the control unit (4). The one or more first sensors (1) may include at least one NOx sensor (5) and at least one CO2 sensor (6). In an embodiment, the control unit (4) may receive CO2 concentration value from at least one CO2 sensor (6) of the vehicle communicatively coupled to the control unit (4).
In an embodiment, the control unit (4) may receive a plurality of combustion parameters of the internal combustion engine (12). The control unit (4) may be communicatively coupled to the engine control module (11) of the vehicle to receive the plurality of combustion parameters of the vehicle. The control unit (4) may compare at least two combustion parameters of the plurality of combustion parameters of the internal combustion engine (12) with at least two combustion threshold values corresponding to the at least two combustion parameters. For sake of explanation, the at least two combustion parameters are illustrated as fuel intake value from the fuel injector (3) of the internal combustion engine (12) and speed of the internal combustion engine (12).

At block 303, the control unit (4) may be configured to determine the intake air-flow of the internal combustion engine (12) based on the NOx concentration value and/or the CO2 concentration value when the speed of the internal combustion engine (12) is greater than the threshold speed and the fuel intake value may be greater than the threshold fuel intake value. The method (300) estimates the intake air-flow of the internal combustion engine (12) by receiving NOx concentration value from the at least one NOx sensor (5) and/or the CO2 concentration value from the at least one CO2 sensor (6) available in the vehicle.
Referring now to Figure 4 which is a flow diagram depicting a method (400) for estimating the intake air-flow of the internal combustion engine (12) based on operation of a fuel injector (3) of the internal combustion engine (12). At block 401, the control unit (4) may be configured to receive a plurality of combustion parameters from the one or more second sensors (2) corresponding to operation of the fuel injector (3). The one or more second sensors (2) may include at least one temperature sensor (7) positioned in a coolant circuit of the internal combustion engine (12), at least one pressure sensor (8) positioned in a manifold of the internal combustion engine (12), an Exhaust Gas Recirculation (EGR) valve sensor (9), an accelerator pedal position sensor (13) and a speed sensor (10). The control unit (4) may be communicatively coupled to the engine control module (11) of the vehicle to receive the plurality of combustion parameters of the vehicle.
The control unit (4) may be communicatively coupled to the engine control module (11) to receive the plurality of combustion parameters of the internal combustion engine (12). The control unit (4) may compare at least two combustion parameters of the plurality of combustion parameters of the internal combustion engine (12) with at least two combustion threshold values corresponding to the at least two combustion parameters. For sake of explanation, the at least two combustion parameters are illustrated as fuel intake value from the fuel injector (3) of the internal combustion engine (12) and speed of the internal combustion engine (12).
At block 402, the control unit (4) may be configured to determine the intake air-flow of the internal combustion engine (12) based on the plurality of combustion parameters received from the one or more second sensors (2), when the at least two combustion parameters may be less than the at least two combustion threshold values i.e., when the speed of the internal combustion engine (12) may be less than the threshold speed and the fuel intake value may be less than the threshold fuel intake value. In the illustrative embodiment, the control unit (4) may be configured to determine the intake air-flow by determining volume of intake air-flow

based on the temperature of the exhaust gas, pressure of the exhaust gas from the plurality of combustion parameters received from the one or more second sensors (2). The method (400) estimates the intake air-flow of the internal combustion engine (12) by the plurality of combustion parameters from the one or more second sensors (2) and eliminates need for a dedicated sensor for measurement of intake air-flow of the internal combustion engine (12). Further, the method (400) may provide substantially uninterrupted intake air-flow measurement of the internal combustion engine (12) thereby resulting in efficient performance of the internal combustion engine (12). Furthermore, elimination of such sensors reduces cost and complexity of the vehicles.
EQUIVALENTS
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare

recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system (100) having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system (100) having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
Referral Numeral:

System 100
One or more first sensors 1
One or more second sensors 2
Fuel injector 3
Control unit 4

NOx sensor 5
CO2 sensor 6
Temperature sensor 7
Pressure sensor 8
EGR valve sensor 9
speed sensor 10
Engine control module 11
Engine 12
Accelerator pedal position sensor 13

We Claim:
1. A method (200) for estimating intake air-flow of an internal combustion engine (12),
the method (200) comprising:
receiving, by a control unit (4), oxygen concentration value in an exhaust gas;
receiving, by the control unit (4), a plurality of combustion parameters of the internal combustion engine (12) corresponding to operation of a fuel injector (3); and
estimating, by the control unit (4), the intake air-flow based on at least one of the oxygen concentration value and the plurality of combustion parameters.
2. The method (200) as claimed in claim 1, comprising:
comparing, by the control unit (4), at least two combustion parameters with at least two combustion threshold values corresponding to the at least two combustion parameters; and
determining, by the control unit (4), the intake air-flow based on the oxygen concentration value if the at least two combustion parameters of the plurality of combustion parameters are greater than the at least two combustion threshold values.
3. The method (200) as claimed in claim 2, comprising determining, by the control unit (4),
the intake air-flow based on the plurality of combustion parameters of the internal combustion engine (12) if the at least two combustion parameters of the internal combustion engine (12) are less than the at least two combustion threshold values.
4. The method (200) as claimed in claim 2, wherein the at least two combustion parameters
of the internal combustion engine (12) comprises a speed of the internal combustion engine (12) and a fuel intake of the internal combustion engine (12).
5. The method (200) as claimed in claim 1, comprising determining, by the control unit
(4), the oxygen concentration value based on a plurality of exhaust parameters
comprising at least one of: NOx concentration value and CO2 concentration value in the
exhaust gas.
6. The method (200) as claimed in claim 1, wherein the plurality of combustion parameters
comprises at least one of exhaust gas temperature, exhaust gas pressure, volumetric

efficiency of the internal combustion engine (12), Exhaust Gas Recirculation (EGR) valve position, an accelerator pedal position, and engine speed.
7. A method (300) for estimating intake air-flow of an internal combustion engine (12), the
method (300) comprising:
receiving, by a control unit (4), NOx concentration value in an exhaust gas of the internal combustion engine (12);
determining, by the control unit (4), oxygen concentration value in the exhaust gas from the internal combustion engine (12), based on the NOx concentration value from the exhaust gas; and
estimating, by the control unit (4), the intake air-flow based on the determined oxygen concentration value from the exhaust gas.
8. The method (300) as claimed in claim 7, comprising:
receiving, by the control unit (4), CO2 concentration value in the exhaust gas; and determining, by the control unit (4), the oxygen concentration value based on the CO2 concentration value.
9. A method (400) for estimating intake air-flow of an internal combustion engine (12)
based on operation of a fuel injector (3), the method (400) comprising:
receiving, by a control unit (4), a plurality of combustion parameters of the
internal combustion engine (12) corresponding to operation of the fuel injector (3); and estimating, by the control unit (4), the intake air-flow based on the plurality of
combustion parameters of the internal combustion engine (12) corresponding to
operation of the fuel injector (3).
10. A system (100) for estimating intake air-flow of an internal combustion engine (12),
comprising:
one or more first sensors (1) configured to detect and transmit oxygen concentration value in an exhaust gas of the internal combustion engine (12);
one or more second sensors (2) configured to detect and transmit a plurality of combustion parameters corresponding to operation of a fuel injector (3); and
a control unit (4) communicatively coupled to the one or more first sensors (1) and the one or more second sensors (2), wherein the control unit (4) configured to:

receive the oxygen concentration value from the exhaust gas sensed by the one or more first sensors (1);
receive the plurality of combustion parameters of the internal combustion engine (12) from the one or more second sensors (2) corresponding to operation of the fuel injector (3); and
estimate the intake air-flow based on at least one of the oxygen concentration value and the plurality of combustion parameters.