Exhaust gas recirculation loop

Abstract

An engine for a vehicle, comprising: an intake duct for directing ambient air to an intake manifold of the engine; an exhaust duct for directing exhaust gas from the engine; an exhaust gas recirculation (EGR) circuit interconnecting the exhaust duct with the intake manifold and for selectively allowing exhaust gas from the exhaust duct to flow into the intake manifold, wherein such exhaust gas mixes with ambient air from the intake duct; and a fresh air bypass conduit interconnecting the intake duct with the EGR circuit and for selectively allowing ambient air from the intake duct to flow into the EGR circuit.

Description

Technical Field

[0001] This disclosure relates to a method for controlling the accumulation of pollutants in the exhaust gas recirculation loop of a vehicle engine. Background Technology

[0002] Internal combustion engines utilize exhaust gas recirculation (EGR) to help reduce throttling losses at low loads, thereby improving knock tolerance and lowering nitrogen oxide (NOx) levels in exhaust gases. EGR is particularly important as an emission reducer for internal combustion engines operating with lean stoichiometry, which are prone to emitting higher concentrations of NOx. In existing EGR loops, water condensation and coking of exhaust system byproducts can lead to pollutant accumulation in the exhaust gas recirculation circuit.

[0003] Therefore, while existing EGR loops have achieved their intended purpose, a new and improved system is still needed, which includes a fresh air bypass line suitable for flushing the EGR loop with fresh air to remove such contaminants. Summary of the Invention

[0004] According to several aspects of this disclosure, an engine for a vehicle includes: an intake manifold for directing ambient air to an intake manifold of the engine; an exhaust manifold for directing exhaust gas from the engine; an exhaust gas recirculation (EGR) circuit that interconnects the exhaust manifold with the intake manifold and is used to selectively allow exhaust gas from the exhaust manifold to flow into the intake manifold, wherein the exhaust gas is mixed with ambient air from the intake manifold; and a fresh air bypass line that interconnects the intake manifold with the EGR circuit and is used to selectively allow ambient air from the intake manifold to flow into the EGR circuit.

[0005] According to another aspect, the EGR circuit includes an exhaust gas control valve that can move between an open state and a closed state, wherein when in the open state, the EGR circuit is activated and the exhaust gas control valve is used to allow exhaust gas to flow through the EGR circuit; when in the closed state, the EGR circuit is deactivated and the exhaust gas control valve is used to prevent exhaust gas from flowing through the EGR circuit; and a fresh air bypass line is connected to the EGR circuit between the exhaust gas control valve and the intake manifold.

[0006] According to another aspect, the fresh air bypass line includes a bypass valve that can move between an open state and a closed state, wherein when in the open state, the bypass valve is used to allow ambient air from the intake duct to flow through the fresh air bypass line and into the EGR circuit, and when in the closed state, the bypass valve is used to prevent ambient air from flowing from the intake duct through the fresh air bypass line and into the EGR circuit.

[0007] On the other hand, when the exhaust gas control valve is closed and the EGR circuit is inactive, the bypass valve is used to allow ambient air from the intake manifold to flow through the fresh air bypass line and into the EGR circuit. The ambient air flows through the EGR circuit to the intake manifold and flushes existing contaminants in the intake manifold with the engine, as well as preventing new contaminants from accumulating in the intake manifold.

[0008] On the other hand, the bypass valve is a passive check valve, wherein when the EGR circuit is active, the exhaust gas pressure flowing through the EGR circuit keeps the bypass valve closed; and when the EGR circuit is inactive, there is no pressure in the EGR circuit, and the bypass valve opens to allow ambient air from the intake pipe to flow through the fresh air bypass line and into the EGR circuit.

[0009] On the other hand, the bypass valve is an active valve that is used to selectively move between an open state, a closed state, and any position in between, thereby allowing a certain flow rate of ambient air from the intake duct to flow through the fresh air bypass line and into the EGR circuit.

[0010] According to another aspect, the bypass valve is one of the following: solenoid valve, ball valve, gate valve, globe valve, butterfly valve, plug valve, pinch valve, diaphragm valve, control valve, piston valve, lift valve, rotary valve, spool valve, or check valve, and is actuated by electronic, pneumatic, hydraulic, or manual means.

[0011] On the other hand, when the exhaust gas control valve is open and the EGR circuit is activated, the bypass valve is used to allow a certain flow of ambient air from the intake pipe to flow through the fresh air bypass line and into the EGR circuit, wherein the ambient air dilutes the exhaust gas flowing through the EGR circuit to the intake manifold.

[0012] On the other hand, the EGR circuit includes an exhaust gas cooler located between the exhaust pipe and the exhaust control valve.

[0013] On the other hand, the exhaust control valve and bypass valve are connected to a controller within the vehicle, which is used to selectively move the exhaust control valve and bypass valve between an open state and a closed state.

[0014] According to several aspects of this disclosure, a method for flushing contaminants from a vehicle engine intake manifold is provided, comprising: directing ambient air to the engine intake manifold via an intake duct; directing exhaust gas from the engine via an exhaust duct; interconnecting the exhaust duct with the intake manifold via an exhaust gas recirculation (EGR) circuit; selectively allowing exhaust gas from the exhaust duct to flow into the intake manifold, in which the exhaust gas mixes with ambient air from the intake duct; interconnecting the intake duct with the EGR circuit via a fresh air bypass duct; and selectively allowing ambient air from the intake duct to flow into the EGR circuit.

[0015] According to several aspects of this disclosure, a vehicle according to exemplary embodiments of this disclosure includes an engine, an intake manifold for directing ambient air to the engine, an exhaust manifold for directing exhaust gas from the engine, an exhaust gas recirculation (EGR) circuit, and a fresh air bypass line. The EGR circuit interconnects the exhaust manifold with the intake manifold and includes an exhaust gas control valve movable between an open and closed state. When in the open state, the EGR circuit is active and the exhaust gas control valve allows exhaust gas to flow through the EGR circuit and into the intake manifold, where the exhaust gas mixes with ambient air from the intake manifold. When in the closed state, the EGR circuit is inactive and the exhaust gas control valve prevents exhaust gas from flowing through the EGR circuit. The fresh air bypass line interconnects the intake duct with the EGR circuit and includes a bypass valve that can move between an open and a closed state. When in the open state, the bypass valve allows ambient air from the intake duct to flow through the fresh air bypass line and into the EGR circuit. When in the closed state, the bypass valve prevents ambient air from flowing from the intake duct through the fresh air bypass line and into the EGR circuit.

[0016] Further applicability will become apparent from the description provided herein. It should be understood that the specification and specific examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0017] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0018] Figure 1 This is a schematic diagram of a vehicle equipped with an internal combustion engine having an exhaust gas recirculation circuit, according to exemplary embodiments of the present disclosure.

[0019] Figure 2 yes Figure 1 A schematic diagram of the internal combustion engine and exhaust gas recirculation circuit of the vehicle shown; and

[0020] Figure 3This is a schematic flowchart of a method according to an exemplary embodiment of the present disclosure.

[0021] These figures are not necessarily drawn to scale, and some features may be enlarged or reduced (e.g., to show details of specific components). In some cases, well-known components, systems, materials, or methods have not been described in detail to avoid obscuring the content of this disclosure. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but should only serve as a representative basis for the claims and to teach those skilled in the art to apply this disclosure in various ways. Detailed Implementation

[0022] The following description is exemplary in nature only and is not intended to limit this disclosure, its application, or its uses. Furthermore, this disclosure is not intended to be bound by any express or implied theory set forth in the foregoing technical fields, background art, summary of the invention, or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals denote the same or corresponding parts and features. The term “module” as used herein refers to any hardware, software, firmware, electronic control components, processing logic, and / or processor device that may be individual or in any combination, and includes, but is not limited to: application-specific integrated circuits (ASICs), electronic circuits, processors (shared, dedicated, or grouped) and memories executing one or more software or firmware programs, combinational logic circuits, and / or other suitable components that provide the said functionality. Although the drawings shown herein depict examples with specific element arrangements, additional intermediate elements, devices, features, or components may be present in actual embodiments. It should also be understood that these drawings are illustrative only and may not be drawn to scale.

[0023] The term "vehicle" as used in this document is not limited to automobiles. While this document primarily describes the technology in the context of automobiles, the technology is not limited to automobiles. These concepts can be used in a wide variety of applications, such as those related to aircraft, ships, other vehicles, and consumer electronics components.

[0024] Exemplary embodiments are provided to make this disclosure more comprehensive and to fully communicate its scope to those skilled in the art. Numerous specific details (e.g., examples of specific compositions, components, apparatuses, and methods) are set forth herein to provide a thorough understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that exemplary embodiments may be embodied in many different forms without the use of specific details, and none of these embodiments should be construed as limiting the scope of this disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0025] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” used herein also include the plural forms. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of the described features, elements, compositions, steps, integrals, operations, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. While the open-ended term “comprising” should be understood as a non-limiting term used to describe and claim the various embodiments described herein, in some aspects it may also be understood as a more restrictive and binding term, such as “consisting of” or “substantially consisting of.” Therefore, for any given embodiment in which compositions, materials, components, elements, features, integrals, operations, and / or process steps are enumerated, this disclosure also specifically includes embodiments that consist of or substantially consist of such enumerated compositions, materials, components, elements, features, integrals, operations, and / or process steps. If "composed of..." is used, the alternative embodiment excludes any additional compositions, materials, parts, elements, features, integrals, operations, and / or process steps. If "essentially composed of..." is used, any additional compositions, materials, parts, elements, features, integrals, operations, and / or process steps that have a substantial effect on the basic and novel characteristics are excluded from the embodiment, but any compositions, materials, parts, elements, features, integrals, operations, and / or process steps that do not have a substantial effect on the basic and novel characteristics may be included in the embodiment.

[0026] Unless explicitly specified as the order of execution, any method steps, processes, and operations described herein should not be construed as requiring performance in the particular order discussed or described. It should also be understood that, unless otherwise stated, additional or alternative steps may be employed.

[0027] When a component, element, or layer is referred to as “located in,” “joined to,” “connected to,” or “coupled to” another component or layer, it may be directly located in, joined to, connected to, or coupled to the other component, element, or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as “directly located in,” “directly joined to,” “directly connected to,” or “directly coupled to” another component or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between…” vs. “directly between…”, “adjacent” vs. “directly adjacent,” etc.). The term “and / or” as used herein includes any and all combinations of one or more of the related listed items.

[0028] Although the terms “first,” “second,” “third,” etc., may be used herein to describe various steps, elements, components, regions, layers, and / or portions, these steps, elements, components, regions, layers, and / or portions should not be limited by these terms unless otherwise stated. These terms are used only to distinguish one step, element, component, region, layer, or portion from another. Unless the context clearly indicates otherwise, the terms “first,” “second,” etc., and other numerical terms used herein do not indicate order or sequence. Therefore, without departing from the teachings of exemplary embodiments, the first step, element, component, region, layer, or portion discussed below may be referred to as the second step, element, component, region, layer, or portion.

[0029] For ease of description, this document may use spatial or temporal relative terms such as “before,” “after,” “inside,” “outside,” “below,” “below,” “lower,” “above,” and “above” to describe the relationship between one element or feature and another, as shown in the figure. In addition to the directions shown in the figure, spatial or temporal relative terms may also cover different orientations of the device or system during use or operation.

[0030] Throughout this disclosure, numerical values ​​represent approximate values ​​or range limits to cover minor deviations from a given value, embodiments substantially the same as the described value, and embodiments exactly the same as the stated value. Except for the working examples provided at the end of the detailed description, all numerical values ​​of parameters (e.g., quantities or conditions) in this specification (including the appended claims) should be understood to be modified in all cases by the term “about,” regardless of whether “about” actually appears before the numerical value. “About” indicates that the numerical value allows for some slight imprecision (the numerical value is close to the exact value; approximately or reasonably close to the value; almost). If the imprecision provided by “about” cannot be otherwise understood in the art to be its usual meaning, then “about” as used herein at least indicates a deviation that may arise from conventional methods of measuring and using such parameters. For example, for percentages, “about” includes a deviation of ±5%; for temperature, “about” includes a deviation of ±5 degrees; for distance, “about” includes a deviation of ±10%. Furthermore, the disclosure of ranges includes disclosing all values ​​as well as further subdivisions throughout the range, including endpoints and subranges given for the range.

[0031] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. According to the exemplary embodiments, Figure 1A vehicle 10 with an associated engine 50 according to various embodiments is shown. The vehicle 10 generally includes a chassis 12, a body 14, front wheels 16, and rear wheels 18. The body 14 is disposed on the chassis 12 and substantially surrounds the components of the vehicle 10. The body 14 and the chassis 12 may together form a frame. The front wheels 16 and the rear wheels 18 are rotatably connected to the chassis 12 near respective corners of the body 14.

[0032] In various embodiments, vehicle 10 is an autonomous vehicle, and system 11 is incorporated into autonomous vehicle 10. Autonomous vehicle 10 is, for example, a vehicle automatically controlled to transport passengers from one location to another. In the illustrated embodiment, vehicle 10 is depicted as a passenger car, but it should be understood that any other vehicle may be used, including motorcycles, trucks, sport utility vehicles (SUVs), recreational vehicles (RVs), etc. The novel features of this disclosure apply to both autonomous and non-autonomous vehicles.

[0033] As shown in the figure, vehicle 10 typically includes a propulsion system 20, a transmission system 22, a steering system 24, a braking system 26, a sensor system 28, an actuator system 30, at least one data storage device 32, a vehicle controller 34, and a communication system 36. In various embodiments, the propulsion system 20 may include an internal combustion engine 50. The transmission system 22 is configured to transmit power from the propulsion system 20 to the front wheels 16 and rear wheels 18 of the vehicle according to an optional speed ratio. According to various embodiments, the transmission system 22 may include a stepped automatic transmission, a continuously variable transmission (CVT), or other suitable transmission. The braking system 26 is configured to provide braking torque to the front wheels 16 and rear wheels 18 of the vehicle. In various embodiments, the braking system 26 may include friction brakes, brake-by-wire brakes, regenerative braking systems (e.g., electric motors), and / or other suitable braking systems. The steering system 24 affects the position of the front wheels 16 and rear wheels 18. Although the steering system 24 is depicted as including a steering wheel for ease of illustration, in some embodiments contemplated within the scope of this disclosure, the steering system 24 may not include a steering wheel.

[0034] Sensor system 28 includes one or more sensing devices 40a-40n for sensing observable conditions of the external and / or internal environment of the autonomous vehicle 10. Sensing devices 40a-40n may include, but are not limited to, radar, lidar, global positioning system, optical camera, thermal imager, ultrasonic sensor, and / or other sensors. In an exemplary embodiment, the plurality of sensing devices 40a-40n includes at least one of a motor speed sensor, a motor torque sensor, an electric drive motor voltage and / or current sensor, an accelerator pedal position sensor, a coolant temperature sensor, a cooling fan speed sensor, a transmission oil temperature sensor, and a sensor for measuring lateral and longitudinal acceleration. In another exemplary embodiment, the plurality of sensing devices 40a-40n further includes sensors for determining information about the environment surrounding the vehicle 10, such as an ambient air temperature sensor, a barometric pressure sensor, and / or a camera and / or video camera for observing the environment in front of the vehicle 10. In another exemplary embodiment, at least one of the plurality of sensing devices 40a-40n is capable of measuring distances in the environment surrounding the vehicle 10. The actuator system 30 includes one or more actuator devices 42a-42n that control one or more features of the vehicle 10, such as, but not limited to, the propulsion system 20, the transmission system 22, the steering system 24, and the braking system 26.

[0035] The vehicle controller 34 includes at least one processor 44 and a computer-readable storage device or medium 46. The at least one data processor 44 can be any custom or commercially available processor, central processing unit (CPU), graphics processing unit (GPU), auxiliary processor among a plurality of processors associated with the vehicle controller 34, semiconductor-based microprocessor (in the form of a microchip or chipset), macroprocessor, any combination thereof, or any device typically used for executing instructions. The computer-readable storage device or medium 46 can include, for example, volatile and non-volatile memory such as read-only memory (ROM), random access memory (RAM), and keep-alive memory (KAM). KAM is a persistent or non-volatile memory used to store various operational variables when at least one data processor 44 is powered off. The computer-readable storage device or medium 46 can be implemented using any of a variety of known storage devices, such as PROM (programmable read-only memory), EPROM (electrically programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), flash memory, or any other electrical, magnetic, optical, or combined storage device capable of storing data, some of which represents executable instructions used by the controller 34 in controlling the vehicle 10.

[0036] The instructions may include one or more separate programs, each comprising an ordered list of executable instructions for implementing logical functions. When executed by at least one processor 44, these instructions receive and process signals from the sensor system 28, execute logic, calculations, methods, and / or algorithms for automatically controlling components of the vehicle 10, and generate control signals to the actuator system 30 to automatically control components of the vehicle 10 based on this logic, calculations, methods, and / or algorithms. Although Figure 1 Only one controller 34 is shown, but embodiments of vehicle 10 may include any number of controllers 34 that communicate via any suitable communication medium or a combination of multiple communication media and cooperate in processing sensor signals, performing logic, calculations, methods and / or algorithms, and generating control signals to automatically control the functions of autonomous vehicle 10.

[0037] The communication system 36 is configured to wirelessly communicate with other remote entities 48, including but not limited to other vehicles (“V2V” communication), infrastructure (“V2I” communication), remote systems, remote servers, cloud computers, and / or personal devices. In one exemplary embodiment, the communication system 36 is a wireless communication system configured to communicate using a wireless local area network (WLAN) based on the IEEE 802.11 standard or using cellular data communication. However, other or alternative communication methods (e.g., Dedicated Short Range Communication (DSRC) channels) are also considered to be within the scope of this disclosure. A DSRC channel refers to a unidirectional or bidirectional short- to medium-range wireless communication channel designed specifically for automotive applications, along with a corresponding set of protocols and standards.

[0038] The vehicle controller 34 is a non-general-purpose electronic control device that includes a pre-programmed digital computer or processor, memory or non-transitory computer-readable medium for storing data (e.g., control logic, software applications, instructions, computer code, data, lookup tables, etc.), and a transceiver [or input / output port]. Computer-readable medium includes any type of media accessible by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, optical disc (CD), digital video disc (DVD), or any other type of memory. "Non-transitory" computer-readable medium does not include wired, wireless, optical, or other communication links that transmit transient electrical or other signals. Non-transitory computer-readable medium includes media that permanently store data and media that store data and subsequently overwrite it, such as rewritable optical discs or erasable storage devices. Computer code includes any type of program code, including source code, object code, and executable code.

[0039] Reference Figure 2In one exemplary embodiment, engine 50 includes an intake manifold 52 and an intake duct 54, the intake duct 54 being used to direct ambient air into the intake manifold 52, as indicated by arrow 88. An exhaust duct 56 is used to direct exhaust gas from engine 50, as indicated by arrow 90. An exhaust gas recirculation (EGR) circuit 58 interconnects the exhaust duct 56 with the intake manifold 52 and is used to selectively allow exhaust gas from the exhaust duct 56 to flow into the intake manifold 52, wherein this exhaust gas mixes with ambient air from the intake duct 54.

[0040] The intake manifold 52 is connected to the cylinder head of the engine 50 and is in fluid communication with the intake passage 54. The throttle body 60 is located within the intake passage and can be configured for one or more purposes, including: (a) airflow control, (b) smooth engine shutdown, and (c) controlling the rate of ambient airflow through the intake manifold 52 to the engine 50.

[0041] As shown in the figure, engine 50 includes a turbocharger 62, which includes an intake side 64 (compressor) located in an intake duct 54 and an air filter 66 located in the intake duct 54. The intake duct 54 defines an air inlet for air to enter the intake manifold 52 through the turbocharger 62. Although a single turbocharger 62 is shown in the figure, it will be understood that this disclosure is equally applicable to devices comprising multiple turbochargers.

[0042] Furthermore, it is understood that this teaching applies to any number of piston-cylinder units and various reciprocating engine configurations, including but not limited to V-type engines, inline engines, horizontally opposed engines, and overhead camshaft and camshaft integrated configurations.

[0043] Exhaust duct 56 is connected to exhaust manifold 68 mounted on engine 50. The exhaust side 70 (turbine) of turbocharger 62 is located in exhaust duct 56 and may include a turbine impeller that communicates with and is driven by the exhaust gas flowing through exhaust duct 56. Exhaust side 70 of turbocharger 62 may include a variable exhaust outlet that controls the exhaust gas flow rate limit through turbocharger 62.

[0044] In one exemplary embodiment, the EGR loop 58 includes an exhaust gas control valve 76 movable between an open state and a closed state. When the exhaust gas control valve 76 is in the open state, the EGR loop 58 is active, and the exhaust gas control valve 76 is used to allow exhaust gas to flow through the EGR loop 58, as indicated by arrow 84. When the exhaust gas control valve is in the closed state, the EGR loop 58 is inactive, and the exhaust gas control valve 76 is used to prevent exhaust gas from flowing through the EGR loop 58.

[0045] Engine 50 also includes a fresh air bypass line 78 that interconnects intake manifold 54 and EGR circuit 58, and is used to selectively allow ambient air from intake manifold 54 to flow into EGR circuit 58, as indicated by arrow 86. Fresh air bypass line 78 is connected to EGR circuit 58 between exhaust gas control valve 76 and intake manifold 52.

[0046] In one exemplary embodiment, the fresh air bypass line 78 includes a bypass valve 80 movable between an open state and a closed state. When the bypass valve 80 is in the open state, it allows ambient air from the intake duct 54 to flow through the fresh air bypass line 78 and into the EGR circuit 58. When it is in the closed state, it prevents ambient air from flowing from the intake duct 54 through the fresh air bypass line 78 and into the EGR circuit 58.

[0047] The controller 82 is used to open and close the exhaust gas control valve 76 to activate or deactivate the EGR circuit 58. The controller 82 may be the vehicle controller 34 or the engine controller, or it may be a separate controller connected to the vehicle controller 34 and / or the engine controller.

[0048] While the EGR circuit 58 is active (exhaust gas is being recirculated), moisture and contaminants in the exhaust gas can cause condensation, water accumulation, and coking within the intake manifold 52. Furthermore, when the EGR circuit 58 is inactive (exhaust gas is not being recirculated), exhaust gas leakage through the exhaust control valve 76 can lead to further accumulation of moisture and contaminants within the intake manifold 52. Excessive condensation and coking within the intake manifold 52 can cause problems including, but not limited to, engine misfires and non-compliance with emission standards.

[0049] Therefore, to prevent the moisture and contaminant levels in the intake manifold 52 from reaching levels that could cause negative side effects, the controller 82 is adapted to actuate the bypass valve 80 to the open state when the exhaust gas control valve 76 is closed and the EGR circuit 58 is inactive. This allows ambient air from the intake duct 54 to flow through the fresh air bypass duct 78 and into the EGR circuit 58, which then flows into the intake manifold 52. The ambient air flowing from the EGR circuit 58 through the intake manifold 52 is flushed away by the engine 50, removing existing moisture and contaminants from the intake manifold 52. As long as the moisture and contaminant levels in the intake manifold 52 are not too high, no negative impact will occur, and any moisture or contaminants will pass smoothly through the engine. Therefore, when the exhaust gas control valve 76 is closed and the EGR circuit 58 is inactive, the controller 82 will continuously seek any opportunity to flush ambient air into the intake manifold 52 through the EGR circuit.

[0050] Furthermore, as long as ambient air flows through the intake manifold 52 from the EGR circuit 58, no additional moisture or contaminants will accumulate. And when the EGR circuit 58 is inactive, the inflow of ambient air into the EGR circuit 58 eliminates the vacuum effect on the exhaust gas control valve 76, thereby reducing exhaust gas leakage through the exhaust gas control valve 76. This reduces the amount of moisture and contaminants entering the EGR circuit 58. Therefore, the flow of ambient air through the EGR circuit 58 to the intake manifold 52 prevents the accumulation of new contaminants within the intake manifold.

[0051] In one exemplary embodiment, the bypass valve 80 is a passive check valve, such as a "baffle" valve. The passive bypass valve 80 operates passively and does not need to communicate with or receive instructions from the controller 82. Instead, when the EGR circuit 58 is active, the exhaust gas pressure flowing through the EGR circuit 58 keeps the bypass valve 80 closed; when the EGR circuit 58 is inactive, there is no pressure (or at least very low pressure) within the EGR circuit 58, and the bypass valve 80 opens under the ambient air pressure flowing within the intake duct 54 to allow ambient air from the intake duct 54 to flow through the fresh air bypass 78 into the EGR circuit 58. When the EGR circuit 58 is active, the exhaust gas pressure within the EGR circuit 58 is higher than the ambient air pressure within the intake duct 54; therefore, if the EGR circuit 58 is active and exhaust gas flows through the circuit, the pressure within the circuit 58 will always keep the passive bypass valve 80 closed.

[0052] In another exemplary embodiment, the bypass valve 80 is an active valve adapted to be selectively actuated by the controller 82 to be in an open (fully open), closed (fully closed) state, or any position in between, thereby allowing a certain flow rate of ambient air from the intake duct 54 to flow through the fresh air bypass duct 78 and into the EGR circuit 58.

[0053] When the exhaust gas control valve 76 is closed and the EGR circuit 58 is inactive, the controller 82 actuates the bypass valve 80 to open, allowing ambient air from the intake manifold 54 to flow through the fresh air bypass line 78 and into the EGR circuit 58. The ambient air then flows through the EGR circuit 58 to the intake manifold 52, flushing out moisture and contaminants from the engine 50.

[0054] In some cases, when the EGR circuit is active, it may be necessary to dilute the exhaust gas before it reaches the intake manifold 52. Therefore, in an exemplary embodiment, when the exhaust control valve 76 is open and the EGR circuit 58 is active, the bypass valve 80 allows a certain flow rate of ambient air from the intake duct 54 to flow through the fresh air bypass duct 78 and into the EGR circuit 58, wherein the ambient air dilutes the exhaust gas flowing through the EGR circuit 58 to the intake manifold 52.

[0055] Those skilled in the art will understand that the exhaust gas control valve 76 and the bypass valve 80 can be any valve suitable for controlling the flow rate of gas through the pipeline. In an exemplary embodiment, both the bypass valve 80 and the exhaust gas control valve 76 are one of a solenoid valve, ball valve, gate valve, globe valve, butterfly valve, plug valve, pinch valve, diaphragm valve, control valve, piston valve, lift valve, rotary valve, spool valve, or check valve, and are actuated by the controller 82 electronically, pneumatically, hydraulically, or manually.

[0056] Reference Figure 3 A method 100 for flushing contaminants from the intake manifold 52 of an engine 50 of a vehicle 10 includes: starting from block 102, guiding ambient air to the intake manifold 52 of the engine 50 via an intake duct 54; at block 104, guiding exhaust gas from the engine 50 via an exhaust duct 56; moving from blocks 102 and 104 to block 106; interconnecting the exhaust duct 56 to the intake manifold 52 via an exhaust gas recirculation (EGR) circuit 58; moving to block 108, selectively allowing exhaust gas from the exhaust duct 56 to flow into the intake manifold 52, wherein such exhaust gas is mixed with ambient air from the intake duct 54; moving to block 110, interconnecting the intake duct 54 and the EGR circuit 58 via a fresh air bypass duct 78; and moving to block 112, selectively allowing ambient air from the intake duct 54 to flow into the EGR circuit 58.

[0057] In one exemplary embodiment, selectively allowing exhaust gas from the exhaust pipe 56 to flow into the intake manifold 52 at block 108 further includes selectively moving an exhaust gas control valve 76 between an open state and a closed state, wherein when in the open state, the EGR circuit 58 is activated and the exhaust gas control valve 76 allows exhaust gas to flow through the EGR circuit 58, and when in the closed state, the EGR circuit 58 is deactivated and the exhaust gas control valve 76 prevents exhaust gas from flowing through the EGR circuit 58. Furthermore, interconnecting the intake pipe 54 and the EGR circuit 58 at block 110 using a fresh air bypass line 78 further includes connecting the fresh air bypass line 78 to the EGR circuit 58 located between the exhaust gas control valve 76 and the intake manifold 52.

[0058] In another exemplary embodiment, selectively allowing ambient air from the intake duct 54 to flow into the EGR circuit 58 at block 112 further includes a bypass valve 80 that selectively moves the fresh air bypass duct 78 between an open state and a closed state, wherein, when in the open state, the bypass valve 80 allows ambient air from the intake duct 54 to flow through the fresh air bypass duct 78 and into the EGR circuit 58, while when in the closed state, the bypass valve 80 prevents ambient air from flowing from the intake duct 54 through the fresh air bypass duct 78 and into the EGR circuit 58.

[0059] In another exemplary embodiment, method 100 further includes: when exhaust gas control valve 76 is closed and EGR circuit 58 is inactive, moving from block 112 to block 114 to move bypass valve 80 of fresh air bypass line 78 to open, so as to allow ambient air from intake duct 54 to flow through fresh air bypass line 78 and into EGR circuit 58, and then through EGR circuit 58 to intake manifold 52, thereby flushing existing contaminants in intake manifold 52 by engine 50 and preventing new contaminants from accumulating in intake manifold 52.

[0060] In another exemplary embodiment, selectively moving the bypass valve 80 of the fresh air bypass line 78 between an open state and a closed state further includes: selectively actuating the bypass valve 80 between an open state, a closed state, and any position in between using a controller 82 that communicates with the bypass valve 80, and allowing a certain flow rate of ambient air from the intake duct 54 to flow through the fresh air bypass line 78 and into the EGR circuit 58, wherein the bypass valve 80 is one of a solenoid valve, ball valve, gate valve, globe valve, butterfly valve, plug valve, pinch valve, diaphragm valve, control valve, piston valve, lift valve, rotary valve, spool valve, or check valve, and is actuated by the controller 82 electronically, pneumatically, hydraulically, or manually.

[0061] In another exemplary embodiment, method 100 further includes: when exhaust gas control valve 76 is open and EGR circuit 58 is active, moving from block 112 to block 116, and using controller 82 to actuate bypass valve 80 to an open state, so as to allow a certain flow rate of ambient air from intake duct 54 to flow through fresh air bypass duct 78 and into EGR circuit 58, and to dilute exhaust gas flowing through EGR circuit 58 to intake manifold 54.

[0062] In another exemplary embodiment, at block 106, interconnecting the exhaust pipe 56 to the intake manifold 52 using the EGR circuit 58 further includes directing exhaust gas through an exhaust gas cooler 72 located between the exhaust pipe 56 and the exhaust gas control valve 76.

[0063] The description in this disclosure is merely exemplary in nature, and variations thereof without departing from the spirit of this disclosure are intended to fall within its scope. Such variations should not be considered as departing from the schemes and scope of this disclosure.

Claims

1. An engine for a vehicle, comprising: An intake duct for directing ambient air to the intake manifold of the engine; An exhaust pipe for guiding exhaust gases from the engine; An exhaust gas recirculation (EGR) circuit interconnects the exhaust pipe to the intake manifold and selectively allows exhaust gas from the exhaust pipe to flow into the intake manifold, wherein such exhaust gas mixes with ambient air from the intake pipe; and A fresh air bypass line interconnects the intake duct and the EGR circuit, and is used to selectively allow ambient air from the intake duct to flow into the EGR circuit.

2. The engine according to claim 1, wherein, The EGR circuit includes an exhaust gas control valve movable between an open state and a closed state, wherein when in the open state, the EGR circuit is active and the exhaust gas control valve allows exhaust gas to flow through the EGR circuit, and when in the closed state, the EGR circuit is inactive and the exhaust gas control valve prevents exhaust gas from flowing through the EGR circuit, and the fresh air bypass line is connected to the EGR circuit between the exhaust gas control valve and the intake manifold.

3. The engine according to claim 2, wherein, The fresh air bypass line includes a bypass valve movable between an open state and a closed state, wherein, when in the open state, the bypass valve allows ambient air from the intake duct to flow through the fresh air bypass line and into the EGR circuit, and when in the closed state, the bypass valve prevents ambient air from flowing from the intake duct through the fresh air bypass line and into the EGR circuit.

4. The engine according to claim 3, wherein, When the exhaust gas control valve is in the closed state and the EGR circuit is in the inactive state, the bypass valve is used to allow ambient air from the intake duct to flow through the fresh air bypass line and into the EGR circuit, wherein the ambient air flows through the EGR circuit to the intake manifold, and: The engine flushes out existing contaminants within the intake manifold; and To prevent new pollutants from accumulating in the intake manifold.

5. The engine according to claim 4, wherein, The bypass valve is a passive check valve, wherein: When the EGR circuit is active, the exhaust gas pressure flowing through the EGR circuit keeps the bypass valve closed; and When the EGR circuit is inactive, there is no pressure in the EGR circuit, and the bypass valve is open to allow ambient air from the intake duct to flow through the fresh air bypass line and into the EGR circuit.

6. The engine according to claim 4, wherein, The bypass valve is an active valve, which is used to selectively move between the open state, the closed state, and any position in between, to allow a certain flow rate of ambient air from the intake duct to flow through the fresh air bypass duct and into the EGR circuit.

7. The engine according to claim 6, wherein, The bypass valve is one of the following: solenoid valve, ball valve, gate valve, globe valve, butterfly valve, plug valve, pinch valve, diaphragm valve, control valve, piston valve, lift valve, rotary valve, spool valve, or check valve, and is actuated electronically, pneumatically, hydraulically, or manually.

8. The engine according to claim 6, wherein, When the exhaust gas control valve is open and the EGR circuit is activated, the bypass valve allows a certain flow rate of ambient air from the intake pipe to flow through the fresh air bypass line and into the EGR circuit, wherein the ambient air dilutes the exhaust gas flowing through the EGR circuit to the intake manifold.

9. The engine according to claim 8, wherein, The EGR circuit includes an exhaust gas cooler located between the exhaust pipe and the exhaust gas control valve.

10. The engine according to claim 9, wherein, The exhaust gas control valve and the bypass valve are connected to a controller within the vehicle, the controller being used to selectively move the exhaust gas control valve and the bypass valve between an open state and a closed state.

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