TECHNICAL FIELD
[0001] The present disclosure relates to, generally, to exhaust gas recirculation 5 systems for internal combustion engines and, more specifically, to an improved exhaust gas recirculation management during a gear shift.
BACKGROUND
[0002] Background description includes information that may be useful in 10 understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Pollutants produced by exhaust from internal combustion engines are of major concern. These pollutants include hydrocarbon, carbon monoxide (CO), nitrogen 15 oxide (NOx), and particulate emissions. The type and amount of emissions depend, among other things, on the type of engine, fuel system, and other operating conditions. For example, diesel engines produce relatively low amounts of CO but produce significant amounts of particulate matter in the form of soot, that is comprised of carbon, ash, that is comprised of inorganics, and polynuclear aromatic hydrocarbons (PAHs), 20 that are condensed about the carbon nuclei of the soot. NOx emissions are also a significant problem for diesel engines.
[0004] NOx emissions arise from reactions occurring during the combustion process which involve nitrogen present in the combustion air (atmospheric nitrogen) or, to a lesser extent, bound in the fuel (fuel-bound nitrogen). NOx formation from atmospheric 25 nitrogen is the dependent on the temperature at which combustion occurs. In other
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words, the greater the temperature in the combustion chamber, the greater the resultant NO
x emissions will be. Conversion of fuel-bound nitrogen to NOx depends on the amount and reactivity of the nitrogen compounds in the fuel and on the amount of oxygen present.
[0005] Among other known techniques, exhaust gas recirculation (EGR) has been 5 successfully used to reduce NOx emissions in the exhaust stream from engines. With EGR techniques, a portion of the exhaust is re-circulated back into the engine. The exhaust gas replaces a portion of the combustion air in the engine, resulting in less oxygen available to enter into the reactions, and lowers the temperature at which combustion occurs. Accordingly, concentration and proportion of different emissions 10 (pre-dominantly NOx) can be controlled.
[0006] EGR is generally governed by an Engine Control Module (ECM) using injected fuel quantity which is also governed by ECU, as one of the parameter. However, during gear shift phase in an AMT (Automatic Manual Transmission), the fuelling is regulated by TCU (Transmission Control Unit),because of which during gear 15 shift phase EGR governing is not as per desired control (since the control parameters, i.e. fuel is not being regulated by ECU).
[0007] Accordingly, there is a need in the state of the art to provide a mechanism by which EGR can be regulated as per desired control even during gear shift phase of the engine. 20
SUMMARY
[0008] This summary is provided to introduce concepts related to exhaust gas recirculation systems for internal combustion engines. 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 25 used to limit the scope of the claimed subject matter.
[0009] In an embodiment, a method for actuating an exhaust gas recirculation (EGR)
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device is described herein. The method begins with ascertaining of whether a gear shift is in progress. Based on affirmative ascertainment, an air quantity set-point is defined as a calibration value. Based on the defined air quantity set-point, an EGR valve of the EGR device is actuated during gear shifting.
[0010] In another embodiment, an engine control unit (ECU) for actuating an 5 exhaust gas recirculation (EGR) device is described. The ECU includes an engine control module (ECM) to ascertain whether a gear shift is in progress, define air quantity set-point to a calibration value based on affirmative ascertainment; and actuate an EGR valve of the EGR device based on the air quantity set-point.
BRIEF DESCRIPTION OF THE DRAWINGS 10
[0011] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein: 15
[0012] FIG. 1 shows an exemplary block diagram of an exhaust gas recirculation (EGR) system in accordance with an embodiment of the present disclosure;
[0013] FIG. 2 shows an engine control unit (ECU) according to an example embodiment of the present disclosure;
[0014] FIGS. 3A and 3B shows a block diagram of an example method 20 implementing a system, to manage EGR during gear shift to improve NOx emissions, in accordance with an embodiment of the present disclosure; and
[0015] FIG. 4 shows an exemplary method according to an embodiment of the present disclosure.
DETAILED DESCRIPTION 25
[0016] The following is a detailed description of embodiments of the disclosure
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depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered 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. 5
[0017] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0018] Each of the appended claims defines a separate invention, which for 10 infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims. 15
[0019] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion 20 or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[0020] In the description herein, the present disclosure pertains to the engines configured with exhaust gas recirculation (EGR) systems to divert at least some exhaust gas from an engine exhaust manifold to an engine intake manifold. By providing a 25 desired engine dilution, such systems reduce engine knock, throttling losses, in-cylinder heat losses, as well as NOx emissions. As a result, fuel economy is improved, especially
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at higher levels of engine boost. Engines have also been configured with a sole cylinder (or cylinder group) that is dedicated for providing external EGR to other engine cylinders. Therein, all of the exhaust from the dedicated cylinder group is re-circulated to the intake manifold. As such, this allows a substantially fixed amount of EGR to be provided to engine cylinders at most operating conditions, providing a flexibility to 5 control emissions and fuel economy by some degree.
[0021] Various approaches may be used to reduce the EGR rate in such dedicated EGR systems during conditions when EGR reduction is required. However, none of the approaches includes a mechanism of operating EGR systems or devices during gear shifting of a vehicle. 10
[0022] To this, the present disclosure provides a method for actuating an exhaust gas recirculation (EGR) device during gear shifts is described herein. The method begins with ascertaining of whether a gear shift is in progress. Based on affirmative ascertainment, an air quantity set-point is defined as a calibration value. Based on the defined air quantity set-point, an EGR valve of the EGR device is actuated during gear 15 shifting.
[0023] In an aspect, before actuating the EGR device during gear shifts, a position sensor disposed in the vicinity of an acceleration pedal constantly determines the position of acceleration pedal. Based on the determined position of the acceleration pedal, it is ascertained that whether the acceleration pedal is pressed beyond a defined 20 threshold. On negative ascertainment, an engine control unit (ECU) defines/sets the air quantity set-point to a base value based on an engine speed checked from signals received from engine speed sensor, a fuel quantity checked from signals received from a fuel injector, a coolant temperature checked from signals received from an atmospheric pressure sensor, and an air temperature checked from signals received from air-flow 25 sensor. However, on positive ascertainment, the ECU defines/sets air quantity set-point to a calibration value, and actuates the EGR valve of the EGR device based on the air quantity set-point.
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[0024] In an example, the calibration value is determined using a calibration map prepared based on engine speed and coolant temperature, and using a calibration array based on atmospheric pressure. In said example, values of the engine speed, the coolant temperature, and the atmospheric pressure are calibrated based on testing to keep NOx value within permissible emission limits. Further, in said example, the ECU checks the 5 engine speed using signals received from an engine speed sensor, checks the coolant temperature from signals received from a coolant temperature sensor, and checks the atmospheric pressure using the signals received from the atmospheric pressure sensor.
[0025] In an aspect, the ascertainment of whether a gear shift is in progress is performed by checking whether transmission control unit (TCU) signal is received by 10 TCU for gear shift, followed by checking whether fuel injection is governed by the TCU for gear shift, based on the TCU signal.
[0026] In an aspect, the ECU further ascertains whether the gear shift has completed using a transmission control unit (TCU) signal for gear.
[0027] In an aspect, following the positive ascertainment of completion of the gear 15 shift, the ECU reverts back the air-quantity set-point to original value based on an engine speed checked from signals received from engine speed sensor, a fuel quantity checked from signals received from a fuel injector, a coolant temperature checked from signals received from an atmospheric pressure sensor, and an air temperature checked from signals received from air-flow sensor. 20
[0028] The above-mentioned advantages, aspects, embodiments, and/or implementations are further described herein with reference to the accompanying figures. It should be noted that the description and figures relate to exemplary implementations/aspects/embodiments, and should not be construed as a limitation to the present disclosure. It is also to be understood that various arrangements may be 25 devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting
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principles, aspects, and embodiments of the present subject matter, as well as specific examples, are intended to encompass equivalents thereof.
[0029] FIG. 1 illustrates an example block diagram of an exhaust gas recirculation (EGR) system 100 in accordance with an embodiment of the present disclosure. The EGR system 100 includes an EGR device 102 coupled to an internal combustion 5 engine 104. In an example, the internal combustion engine 104 is a diesel engine. The internal combustion engine 104 may include one or more combustion chambers arranged in any convenient manner such as in line or in a V-shaped configuration. Thus, the EGR system 102 may be employed in conjunction with an internal combustion engine having a straight 4, straight 6, V-6, V-8, V-10 cylinder 10 arrangements or the like. Furthermore, those having ordinary skill in the art will appreciate that the number and particular arrangement of the combustion chambers of the internal combustion engine form no part of the present disclosure.
[0030] In addition to the internal combustion engine 104, the EGR module 102 is also communicatively coupled to an engine control unit (ECU) 106 for its actuation 15 based on a predefined criterion. For activation of EGR module 102, the ECU 106 is communicatively coupled to an acceleration pedal position sensor 108 to ascertain position of an acceleration pedal, an engine speed sensor 110 to receive signals pertaining to engine speed, a fuel injector 112 to receive signals pertaining to fuel quantity injected, a coolant temperature sensor 114 to receive signals pertaining to 20 coolant temperature, an atmospheric pressure sensor 116 to receive signals pertaining to atmospheric pressure, an air-flow sensor 118 to receive signals pertaining to air temperature, and a transmission control unit (TCU) 120 to ascertain whether gear shifting is in progress.
[0031] FIG. 2 illustrates an example of the ECU 106 for actuating the EGR device 25 102 during gear shifting in accordance with an example of the present disclosure. The ECU 106 may be implemented as a standalone device communicatively connected through a network to other devices such as the acceleration pedal position sensor 108,
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the engine speed sensor 110, the fuel injector 112, the coolant temperature sensor 114, the atmospheric pressure sensor 116, the air-flow sensor 118, the transmission control unit (TCU) 120, and the like.
[0032] The ECU 106 includes an interface(s) 202 and memory 204. The interface(s) 202 may include a variety of interfaces. The interface(s) 202 may also 5 provide a communication pathway for one or more components of the ECU 106.
[0033] The ECU 106 may include one or more processor(s) 206 and an engine control module (ECM) 208.
[0034] The one or more processor(s) 206 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central 10 processing units, logic circuitries, and/or any devices that manipulate data based on operational instructions.
[0035] The ECM 208 may be implemented as a combination of hardware and programming (for example, programmable instructions) to implement one or more functionalities of the ECM 208. In examples described herein, such combinations of 15 hardware and programming may be implemented in several different ways. For example, the programming for the ECM 208 may be processor executable instructions stored on a non-transitory machine-readable storage medium and the hardware for the ECM 208 may include a processing resource (for example, one or more processors), to execute such instructions. In the present examples, the machine-20 readable storage medium may store instructions that, when executed by the processing resource, implement the ECM 208. In such examples, the ECU 106 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 106 and the processing resource. 25 In other examples, the ECM 208 may be implemented by electronic circuitry.
[0036] The operation of the ECU 106 is described with the flowchart 300
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represented in FIG. 3. In operation, at block 302, the ECM 208 determines the position of acceleration pedal based on signals received from the accelerator pedal position sensor 108 disposed in the vicinity of the acceleration pedal. Based on the determined position of the acceleration pedal, the ECM 208 ascertains whether the acceleration pedal is pressed beyond a defined threshold in block 304. 5
[0037] On negative ascertainment, in block 306, the ECM 208 or ECU 106 defines/sets the air quantity set-point to a base value based on an engine speed checked from signals received from engine speed sensor, a fuel quantity checked from signals received from a fuel injector, a coolant temperature checked from signals received from an atmospheric pressure sensor, and an air temperature checked from signals received 10 from air-flow sensor.
[0038] However, on positive ascertainment, in block 308, the ECM 208 or ECU 106 defines/sets air quantity set-point to a calibration value, and actuates the EGR valve of the EGR device based on the air quantity set-point.
[0039] In an example, the calibration value is determined using a calibration map 15 prepared based on engine speed and coolant temperature, and using a calibration array based on atmospheric pressure. In said example, values of the engine speed, the coolant temperature, and the atmospheric pressure are calibrated based on testing to keep NOx value within permissible emission limits. Further, in said example, the ECU checks the engine speed using signals received from an engine speed sensor, checks the coolant 20 temperature from signals received from a coolant temperature sensor, and checks the atmospheric pressure using the signals received from the atmospheric pressure sensor.
[0040] Continuing with the present disclosure, in case of positive ascertainment, the ECM 208 or ECU 106 continuously ascertains whether a gear shift is in progress (block 310). Based on affirmative ascertainment, the ECM 208 or ECU 106 defines 25 air quantity set-point to a calibration value (block 312), and actuates an EGR valve of the EGR device 102 based on the air quantity set-point (block 314).
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[0041] In an example implementation, the ECM 208 or ECU 106 ascertains whether a gear shift is in progress by checking whether transmission control unit (TCU) signal is received by the TCU 120 for gear shift, and checking whether fuel injection is governed by the TCU 120 for gear shift, based on the TCU signal.
[0042] In an example implementation, the ECM 208 or ECU 106 defines air 5 quantity set-point to a calibration value is based on an engine speed, a coolant temperature, and an atmospheric pressure.
[0043] In an example implementation, the ECM 208 or ECU 106 checks the engine speed using signals received from an engine speed sensor, checks the coolant temperature from signals received from a coolant temperature sensor, and checks the 10 atmospheric pressure using the signals received from the atmospheric pressure sensor.
[0044] Further, once the EGR valve of the EGR device 102 is actuated during a gear shift, the ECM 208 or ECU 106 further ascertain whether the gear shift has completed using a transmission control unit (TCU) signal for gear (block 316). On 15 positive ascertainment, the ECM 208 or ECU 106 reverts back the air-quantity set-point to original value based on an engine speed checked from signals received from engine speed sensor, a fuel quantity checked from signals received from a fuel injector, a coolant temperature checked from signals received from an atmospheric pressure sensor, and an air temperature checked from signals received from air-flow 20 sensor.
[0045] FIG. 4 illustrates an example method 400 for actuating an EGR valve during gear shift in accordance with an embodiment of the present disclosure. 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 may be combined in any 25 order to implement the methods, or an alternative method. Furthermore, method 400 may be implemented by processing resource or ECU 106 through any suitable
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hardware, non-transitory machine-readable instructions, or combination thereof.
[0046] At block 402, the ECM 208 or ECU 106 continuously ascertains whether a gear shift is in progress.
[0047] At block 404, based on affirmative ascertainment, the ECM 208 or ECU 106 defines air quantity set-point to a calibration value. 5
[0048] At block 406, the ECM 208 or ECU 106 actuates an EGR valve of the EGR device 102 based on the air quantity set-point.
[0049] Thus, with the actuation of the EGR valve of the EGR device 102 during the gear shift, calibrated value of exhaust will be recirculated into the engine resulting in improvement in emissions (considerably NOx).. 10
[0050] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details. 15
[0051] 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 “processing,” or “ascertaining,” or “receiving,” or 20 “actuating,” or “determining,” “defining,” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such 25 information storage, transmission or display devices.
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[0052] 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, 5 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.
[0053] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and 10 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.
[0054] Although examples for the present disclosure have been described in language specific to structural features and/or methods, it should be understood that 15 the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained as examples of the present disclosure.

We claim:
1. A method for actuating an exhaust gas recirculation (EGR) device, comprising:
ascertaining whether a gear shift is in progress;
based on affirmative ascertainment, defining air quantity set-point to a calibration value; and 5
actuating an EGR valve of the EGR device based on the air quantity set-point.
2. The method as claimed in claim 1, wherein the ascertaining whether a gear shift is in progress, comprises:
checking whether transmission control unit (TCU) signal is received by the TCU for gear shift; and
checking whether fuel injection is governed by the TCU for gear shift, based on the TCU signal.
3. The method as claimed in claim 1, wherein the defining air quantity set-point to a calibration value is based on an engine speed, a coolant temperature, and an atmospheric pressure.
4. The method as claimed in claim 3, wherein checking by an Engine Control Unit 20 (ECU):
checking the engine speed using signals received from an engine speed sensor;
checking the coolant temperature from signals received from a coolant temperature sensor; and
checking the atmospheric pressure using the signals received from the atmospheric pressure sensor.
5. The method as claimed in claim 1, further comprising ascertaining whether the gear shift has completed using a transmission control unit (TCU) signal for gear.
6. The method as claimed in claim 5, further comprising reverting back the air-quantity set-point to original value based on an engine speed checked from signals 10 received from engine speed sensor, a fuel quantity checked from signals received from a fuel injector, a coolant temperature checked from signals received from an atmospheric pressure sensor, and an air temperature checked from signals received from air-flow sensor.
7. The method as claimed in claim 1, further comprising:
determining the position of acceleration pedal based on signals received from a position sensor disposed in the vicinity of the acceleration pedal;
ascertaining whether the acceleration pedal is pressed beyond a defined threshold based on the determined position of the acceleration pedal; 20
on negative ascertainment,
defining, by an engine control unit (ECU), the air quantity set-point to a base value based on an engine speed checked from signals received from engine speed sensor, a fuel quantity checked from signals received from a fuel injector, a coolant temperature checked from signals received 25
from an atmospheric pressure sensor, and an air temperature checked from signals received from air-flow sensor; and
on positive ascertainment,
defining, by the ECU, the air quantity set-point to a calibration value, and 5
actuating the EGR valve of the EGR device based on the air quantity set-point.
8. An engine control unit (ECU) for actuating an exhaust gas recirculation (EGR) device, comprising:
an engine control module (ECM) to: 10
ascertain whether a gear shift is in progress;
based on affirmative ascertainment, define air quantity set-point to a calibration value; and
actuate an EGR valve of the EGR device based on the air quantity set-point. 15
9. The ECU as claimed in claim 8, wherein the ECM ascertains whether a gear shift is in progress, by:
checking whether transmission control unit (TCU) signal is received by TCU for gear shift; and 20
checking whether fuel injection is governed by the TCU for gear shift, based on the TCU signal.
10. The ECU as claimed in claim 8, wherein the ECM defines air quantity set-point to a calibration value is based on an engine speed, a coolant temperature, and an atmospheric pressure.
11. The ECU as claimed in claim 10, wherein the ECM is to:
check the engine speed using signals received from an engine speed sensor;
check the coolant temperature from signals received from a coolant temperature sensor; and
check the atmospheric pressure using the signals received from the 10 atmospheric pressure sensor.
12. The ECU as claimed in claim 8, wherein the ECM is to further ascertain whether the gear shift has completed using a transmission control unit (TCU) signal for gear. 15
13. The ECU as claimed in claim 12, wherein the ECM is to revert back the air-quantity set-point to original value based on an engine speed checked from signals received from engine speed sensor, a fuel quantity checked from signals received from a fuel injector, a coolant temperature checked from signals received from an 20 atmospheric pressure sensor, and an air temperature checked from signals received from air-flow sensor.
14. The ECU as claimed in claim 8, wherein the ECM is to further:
determine the position of acceleration pedal based on signals received from a position sensor disposed in the vicinity of the acceleration pedal;
ascertain whether the acceleration pedal is pressed beyond a defined threshold based on the determined position of the acceleration pedal;
on negative ascertainment,
define the air quantity set-point to a base value based on an engine speed checked from signals received from engine speed sensor, a fuel quantity checked from signals received from a fuel injector, a coolant temperature checked from signals received from an atmospheric pressure sensor, and an air temperature checked from signals received from air-10 flow sensor; and
on positive ascertainment,
define the air quantity set-point to a calibration value, and
actuate the EGR valve of the EGR device based on the air quantity set-point.