Exhaust temperature control

Abstract

A vehicle engine adapted to control an exhaust gas temperature (EGT) at a catalyst inlet includes an EGT sensor in communication with a system controller and adapted to measure the exhaust gas temperature at the catalyst inlet, the system controller being adapted to compare the measured EGT to a target EGT and, when the measured EGT is greater than the target EGT, to determine that the catalyst inlet is an exhaust gas temperature at the catalyst inlet. Gas exchange within cylinders within the engine is limited during an intake stroke, and turbine efficiency of a variable geometry turbocharger of the engine is increased by increasing boost from the variable geometry turbocharger.

Description

Technical Field

[0001] This disclosure relates to an engine for a vehicle that is adapted to control the exhaust gas temperature (EGT) at the catalyst inlet. Background Technology

[0002] In an internal combustion engine, as gases pass through the exhaust system, exhaust gases from the cylinders are guided through the catalyst (catalytic converter). High EGT at the catalyst affects its performance and durability.

[0003] Therefore, while current systems and methods have achieved their intended purpose, there is still a need for new and improved engines and methods for controlling the temperature of exhaust gas from engines. Summary of the Invention

[0004] According to several aspects of this disclosure, a method for controlling exhaust temperature within a vehicle engine includes: measuring the temperature of exhaust gas at a catalyst inlet (exhaust temperature, EGT) using an EGT sensor communicating with a system controller; comparing the measured EGT with a target EGT using the system controller; and when the measured EGT is greater than the target EGT, limiting gas exchange within the cylinders of the engine during the intake stroke using the system controller; and increasing the turbine efficiency of a variable geometry turbocharger of the engine by increasing boost pressure from a turbocharger using the system controller.

[0005] According to another aspect, the method also includes adjusting the gas exchange during the intake stroke in the engine cylinder using a system controller to increase the EGT when the measured EGT is less than the target EGT.

[0006] According to another aspect, the method also includes maintaining the current gas exchange calibration in the cylinder by the system controller when the measured EGT equals the target EGT, or limiting the gas exchange in the cylinder during the intake stroke by the system controller, and increasing the turbine efficiency of the variable geometry turbocharger of the engine by increasing the boost from the turbocharger by the system controller.

[0007] According to another aspect, limiting gas exchange in the cylinder during the intake stroke using a system controller also includes: using the system controller to close the intake valve for the cylinder in advance during the intake stroke and reducing the volume of the air-fuel mixture received in the cylinder during the intake stroke.

[0008] According to another aspect, closing the intake valve for the cylinder in advance using the system controller during the intake stroke also includes adjusting the timing of the intake camshaft associated with the intake valve using a cam phaser that communicates with the system controller.

[0009] According to another aspect, adjusting the timing of the intake cam associated with the intake valve using a cam phaser also includes adjusting the timing of the short-duration intake camshaft associated with the intake valve using a cam phaser.

[0010] According to another aspect, the method also includes adjusting spark timing based on the advance of intake valve closing.

[0011] According to another aspect, increasing boost from the variable geometry turbocharger using a system controller also includes: adjusting the angle of each of a plurality of movable blades surrounding the turbine using the system controller, the blades being in communication with the system controller and adapted to control the exhaust flow through the turbine of the variable geometry turbocharger.

[0012] According to another aspect, increasing boost from the variable geometry turbocharger also includes: directing all exhaust from the engine through the turbine of the variable geometry turbocharger.

[0013] According to another aspect, increasing the boost from the variable geometry turbocharger also includes increasing the enthalpy extraction from the exhaust gas guided through the turbine of the variable geometry turbocharger.

[0014] According to several aspects of this disclosure, a vehicle engine suitable for controlling exhaust gas temperature (EGT) at the catalyst inlet includes an EGT sensor that communicates with a system controller and is adapted to measure the exhaust gas temperature at the catalyst inlet. The system controller is adapted to compare the measured EGT with a target EGT, and when the measured EGT is greater than the target EGT, to restrict gas exchange within the cylinders of the engine during the intake stroke, and to increase the turbocharger efficiency of the engine's variable geometry turbocharger by increasing boost from the variable geometry turbocharger.

[0015] According to another approach, when the measured EGT is less than the target EGT, the system controller is adapted to adjust the gas exchange during the intake stroke in the engine cylinder to increase the EGT.

[0016] According to another aspect, when the measured EGT equals the target EGT, the system controller is adapted to one of the following: maintain the current gas exchange calibration in the cylinder during the intake stroke, or limit the gas exchange in the cylinder, and increase the turbo efficiency of the engine's variable geometry turbocharger by increasing the boost from the variable geometry turbocharger.

[0017] According to another aspect, when limiting gas exchange within the cylinder during the intake stroke, the system controller is also adapted to close the intake valve for the cylinder in advance during the intake stroke and reduce the volume of the air-fuel mixture received within the cylinder during the intake stroke.

[0018] According to another aspect, when the intake valve of the cylinder is closed early during the intake stroke, the system controller is also adapted to actuate the cam phaser connected to the system controller and to adjust the timing of the intake camshaft associated with the intake valve.

[0019] On the other hand, the intake camshaft associated with the intake valve is a short-duration intake cam.

[0020] On the other hand, the system controller is also adapted to adjust the spark timing in the cylinder based on the advance of intake valve closing.

[0021] According to another aspect, a variable geometry turbocharger includes a turbine having multiple movable blades adapted to guide exhaust flow through the turbine, and a system controller adapted to selectively adjust the angle of each of the multiple movable blades to increase boost from the variable geometry turbocharger.

[0022] On the other hand, all exhaust from the engine is directed through the turbine of the variable geometry turbocharger, increasing the boost from the variable geometry turbocharger and increasing the enthalpy extraction from the exhaust directed through the turbine of the variable geometry turbocharger.

[0023] Further areas of application will become clear from the description provided herein. It should be understood that the specification and specific embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0024] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0025] Figure 1 It is a perspective view of a vehicle having an engine according to an exemplary embodiment of the present disclosure;

[0026] Figure 2 yes Figure 1 A schematic diagram of the internal combustion engine of the vehicle shown.

[0027] Figure 3 yes Figure 2 The schematic diagram shown illustrates the internal combustion engine, and this example diagram illustrates the details of a variable geometry turbocharger;

[0028] Figure 4A This is a side view of the turbine of a variable geometry turbocharger, where the movable blades are relatively closed, thus providing a low exhaust flow to the turbine blades;

[0029] Figure 4B It is similar to Figure 4AA side-section diagram showing that these movable blades are relatively open, thus providing a higher exhaust flow to these turbine blades;

[0030] Figure 4C Is it like this? Figure 4A The middle is marked as " Figure 4C The circled area shows an enlarged view of the movable blades of the turbine;

[0031] Figure 5 yes Figure 1 , Figure 2 and Figure 3 The shown is a cross-sectional side view of the engine cylinder; and

[0032] Figure 6 This is a flowchart illustrating a method according to an exemplary embodiment of the present disclosure.

[0033] These figures are not necessarily to scale, and some features may be enlarged or reduced to show details, such as those of specific components. In some cases, well-known components, systems, materials, or methods are not described in detail to avoid obscuring this disclosure. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a basis for the claims and as a representative basis for teaching those skilled in the art to use this disclosure in various ways. Detailed Implementation

[0034] The following description is merely exemplary in nature and is not intended to limit this disclosure, application, or use. Furthermore, it is not intended to be construed as being bound by any express or implied theory presented in the foregoing technical fields, background art, summary of the invention, or the following detailed description. It should be understood that in all the drawings, corresponding reference numerals denote the same or corresponding parts and features. As used herein, the term "module" individually or in any combination refers to any hardware, software, firmware, electronic control components, processing logic, and / or processor device, including but not limited to: ASICs, electronic circuits, processors (shared, specific, or grouped) and memories executing one or more software or firmware programs, combinational logic circuits, and / or other suitable components providing that functionality. While the drawings shown herein depict examples with certain element arrangements, additional intermediate elements, devices, features, or components may be present in actual embodiments. It should also be understood that the drawings are merely illustrative and may not be drawn to scale.

[0035] As used herein, the term "vehicle" is not limited to automobiles. While this article primarily describes the technology in the context of automobiles, the technology is not limited to automobiles. These concepts can be used in a variety of applications, such as those relating to aircraft, ships, other vehicles, and consumer electronics components.

[0036] Exemplary embodiments are provided so that this disclosure will be thorough and will fully communicate the scope to those skilled in the art. Numerous specific details, such as examples of specific components, parts, apparatuses, and methods, are set forth to provide a thorough understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that specific details are not required, exemplary embodiments may be embodied in many different forms, and should not 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.

[0037] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “include,” and “having” are inclusive and thus specify the presence of the feature, element, composition, step, integer, operation, and / or part, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups 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, the term may alternatively be understood as a more restrictive and limiting term, such as "consisting of" or "substantially consisting of." Therefore, for any given embodiment that describes a composition, material, component, element, feature, integral, operational, and / or method step, this disclosure also specifically includes embodiments that consist of or substantially consist of those described compositions, materials, components, elements, features, integrals, operational, and / or method steps. In the case of "consisting of," alternative embodiments may exclude any additional compositions, materials, components, elements, features, integrals, operational, and / or process steps, while in the case of "substantially consisting of," any additional compositions, materials, components, elements, features, integrals, operational, and / or process steps that substantially affect the basic and novel characteristics are excluded from the embodiments herein, but any compositions, materials, components, elements, features, integrals, operational, and / or process steps that do not substantially affect the basic and novel characteristics may be included in the embodiments.

[0038] Any methods, steps, procedures, and operations described herein should not be construed as necessarily requiring them to be performed in the specific order discussed or shown, unless explicitly identified as such. It should also be understood that, unless otherwise stated, alternative or alternative steps may be employed.

[0039] When a component, element, or layer is referred to as being “on,” “joined to,” “connected to,” or “coupled to” another component or layer, it may be directly joined, connected to, or coupled to the other component, element, or layer, or there may be intermediate elements or layers. Conversely, when an element is referred to as being “directly on,” “directly joined to,” “directly connected to,” or “directly coupled to” another component or layer, there may be no intermediate elements or layers. 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.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0040] Although the terms first, second, third, etc., may be used herein to describe various steps, elements, components, regions, layers, and / or sections, these steps, elements, components, regions, layers, and / or sections should not be limited by these terms unless otherwise indicated. These terms may be used only to distinguish one step, element, component, region, layer, or portion from another. Terms such as “first,” “second,” and other numerical terms used herein do not imply order or sequence unless the context clearly indicates otherwise. Therefore, 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 without departing from the teachings of the exemplary embodiments.

[0041] Spatially or temporally relative terms such as “before,” “after,” “inside,” “outside,” “below,” “below,” “lower,” “above,” “upper,” etc., may be used herein to describe the relationship between one element or feature and another element or feature as shown in the figures. Spatially or temporally relative terms may be intended to cover different orientations of the device or system in use or operation other than those depicted in the figures.

[0042] Throughout this disclosure, numerical values ​​represent approximate measurements or limitations of a range to cover minor deviations from a given value and embodiments with values ​​mentioned by "about" as well as embodiments with values ​​mentioned by precision. Except in 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 by the term "about" in all cases, regardless of whether "about" actually appears before the numerical value. "About" indicates that the numerical value allows for some slight inaccuracy (some method of approximating correctness in the numerical value; approximately or reasonably close to the value; near). If the inaccuracy provided by "about" is not understood in this ordinary sense in the art, then "about" as used herein at least indicates a variation that can be caused by common methods of measuring and using such parameters. For example, "about" with respect to percentages includes a variation of plus / minus 5%, "about" with respect to temperature includes a variation of plus / minus 5 degrees, and "about" with respect to distance includes a variation of plus / minus 10%. Furthermore, the disclosure of ranges includes the disclosure of all values ​​throughout the range and further subdivisions of the range, including endpoints and subranges given for the range. Furthermore, the disclosure of the range includes all values ​​throughout the entire range and the disclosure of further subdivisions of the range, including endpoints and subranges given for the range.

[0043] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. According to the exemplary embodiments, Figure 1 A vehicle 10 is shown with an internal combustion engine 20 adapted to control the exhaust gas temperature (EGT) at the catalyst inlet 50. The vehicle 10 typically includes a chassis 12, a body 14, front wheels 16, and rear wheels 18. The body 14 is mounted on the chassis 12 and generally surrounds the components of the vehicle 10. The body 14 and chassis 12 may together form a frame. The front wheels 16 and rear wheels 18 are each rotatably connected to the chassis 12 near a corresponding corner of the body 14.

[0044] In various embodiments, vehicle 10 is an autonomous vehicle. Autonomous vehicle 10 is, for example, a vehicle 10 automatically controlled to transport passengers from one location to another. Vehicle 10 is depicted as a passenger car in the illustrated embodiment, but it should be understood that any other vehicle, including motorcycles, trucks, sport utility vehicles (SUVs), recreational vehicles (RVs), etc., may also be used. In one exemplary embodiment, vehicle 10 is equipped with a so-called Level 4 or Level 5 automation system. A Level 4 system signifies “high automation,” referring to the driving mode-specific performance of an automated driving system in all aspects of a dynamic driving task, even when a human user does not properly respond to intervention requests. A Level 5 system signifies “full automation,” referring to the full-time performance of an automated driving system in all aspects of a dynamic driving task under all road and environmental conditions manageable by a human driver. Novel aspects of this disclosure also apply to non-autonomous vehicles.

[0045] As shown, vehicle 10 typically includes an internal combustion engine 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 wireless communication system 36. The transmission system 22 is configured to transmit power from engine 20 to the front wheels 16 and rear wheels 18 of the vehicle according to a selectable speed ratio. Depending on the embodiment, the transmission system 22 may include a graded automatic transmission, a continuously variable transmission, or a 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, line brakes, regenerative braking systems such as those using 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 depicted as including a steering wheel for illustrative purposes, in some embodiments contemplated within the scope of this disclosure, such as for fully autonomous vehicles, the steering system 24 may not include a steering wheel.

[0046] Sensor system 28 includes one or more sensing devices 40a-40n that sense the viewing 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. Cameras may include two or more digital cameras at a selected distance, wherein the two or more digital cameras are used to acquire stereoscopic images of the surrounding environment to obtain a three-dimensional image or map. Multiple sensing devices 40a-40n are used to determine information about the environment surrounding the vehicle 10. In one exemplary embodiment, multiple sensing devices 40a-40n include 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, and a transmission oil temperature sensor. In another exemplary embodiment, multiple sensing devices 40a-40n also include sensors for determining information about the environment surrounding the vehicle 10, such as an ambient air temperature sensor, an atmospheric pressure sensor, and / or a photographic and / or video camera positioned to view 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.

[0047] 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 several 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 volatile and non-volatile storage, such as read-only memory (ROM), random access memory (RAM), and keep-alive memory (KAM). KAM is persistent or non-volatile memory that can be 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 memory devices, such as PROM (programmable read-only memory), EPROM (electrical PROM), EEPROM (electrically erasable PROM), flash memory, or any other electrical, magnetic, optical, or combined memory device capable of storing data, some of which represents executable instructions used by the controller 34 in controlling the vehicle 10.

[0048] The instructions may include one or more separate programs, each including an ordered list of executable instructions for implementing logical functions. When executed by at least one processor 44, the 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 based on the logic, calculations, methods, and / or algorithms to automatically control components of the vehicle 10. Although in 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 combination of communication media and cooperate to process sensor signals, execute logic, calculations, methods and / or algorithms, and generate control signals to automatically control the features of autonomous vehicle 10.

[0049] In various embodiments, one or more instructions from the vehicle controller 34 are included in the trajectory planning system and, when executed by at least one data processor 44, generate a trajectory output that addresses the kinematic and dynamic constraints of the environment. For example, the instructions receive process sensor and map data as input. The instructions execute a graph-based method with a customized cost function to handle different road scenarios in urban and highway areas.

[0050] Wireless communication system 36 is configured to wirelessly transmit information to and from other remote entities 48, such as, 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, communication system 36 is a wireless communication system configured to communicate using the IEEE 802.11 standard or via a wireless local area network (WLAN) using cellular data communication. However, other or alternative communication methods, such as specific short-range communication (DSRC) channels, are also considered within the scope of this disclosure. A DSRC channel refers to a unidirectional or bidirectional short- to medium-range wireless communication channel specific to automotive applications, and the corresponding set of protocols and standards.

[0051] 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 such as 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, disc compaction (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 in which data can be permanently stored and media in which data can be stored and later rewritten, such as rewritable optical discs or erasable memory devices. Computer code includes any type of program code, including source code, object code, and executable code.

[0052] Reference Figure 2 and Figure 3 The internal combustion engine 20 includes a cylinder block 52 in which a plurality of cylinders 54 are arranged. As shown, the engine 20 also includes a cylinder head 56. Each cylinder 54 includes a piston 58 configured to reciprocate therein. A combustion chamber 60 is formed within the cylinder 54 between the bottom surface of the cylinder head 56 and the top surface of the piston 58. As those skilled in the art will know, the combustion chamber 60 is configured to receive a fuel-air mixture for subsequent combustion therein.

[0053] Engine 20 also includes a crankshaft 62 configured to rotate within cylinder block 52. The crankshaft 62 is rotated by piston 58 as a properly proportioned fuel-air mixture burns in combustion chamber 60. After the fuel-air mixture has burned in a specific combustion chamber 60, the reciprocating motion of the specific piston 58 is used to expel afterburner gases 64 from a corresponding cylinder 54. Engine 20 also includes a fluid pump 66. Fluid pump 66 is configured to supply a lubricating fluid 68, such as engine oil. Thus, fluid pump 66 can supply lubricating fluid 68 to various bearings, such as those of the crankshaft 62. Fluid pump 66 may be driven directly by engine 20 or by an electric motor (not shown).

[0054] Engine 20 also includes a sensing system 70 configured to direct airflow 72 from the ambient environment to cylinders 54. Sensing system 70 includes an intake duct 74, a variable geometry turbocharger 76, and an intake manifold 78. Sensing system 70 may also include an air filter 79 located upstream of the variable geometry turbocharger 76 for removing foreign particles and other airborne debris from the airflow 72. Intake duct 74 is configured to direct airflow 72 from the ambient environment to the variable geometry turbocharger 76, which is configured to pressurize the received airflow and discharge the pressurized airflow into the intake manifold 78. Intake manifold 78 then distributes the previously pressurized airflow 72 to cylinders 54 for mixing with an appropriate amount of fuel, and subsequently combustion of the resulting fuel-air mixture. Those skilled in the art will understand that the novel features of this disclosure are also applicable to engines using port injection or a combination of direct / port injection systems.

[0055] The variable geometry turbocharger 76 includes a shaft 80 having a first end and a second end. A turbine 82 is mounted on the shaft 80 near the first end and is configured to rotate about an axis together with the shaft 80 via afterburner gas 64 discharged from the cylinder 54. The turbine 82 is located within a housing 84, through which exhaust gas 64 from the engine 20 enters the housing 84, flows through the turbine 82 and to the catalyst 50 (catalytic converter), and then exits through the exhaust pipe 86 of the vehicle 10. The variable geometry turbocharger 76 also includes a compressor impeller 88 mounted on the shaft 80 near the second end. The compressor impeller 88 is driven by the rotation of the turbine via the shaft 80 due to the rotating exhaust gas 64 flow delivered to the turbine 82. The compressor impeller 88 is configured to pressurize the airflow 72 received from the ambient environment for final delivery to the cylinder 54. Thus, rotation is transmitted to the shaft 80 by the afterburner exhaust gas 64 energizing the turbine 82, and this rotation is in turn transmitted to the compressor impeller 88 because the compressor impeller 88 is mounted on the shaft 80. As understood by those skilled in the art, the variable flow rate and force of the post-combustion exhaust 64 affect the amount of boost pressure generated by the compressor impeller 88 throughout the entire operating range of the engine 20.

[0056] Reference Figure 4A , Figure 4B and Figure 4C In one exemplary embodiment, the turbine 82 of the variable geometry turbocharger 76 includes a plurality of movable blades 90 that selectively control the exhaust flow through the turbine 82. As indicated by arrow 94, the plurality of movable blades 90 rotate about their own axis 92, wherein the blades 90 can be in a more "open" or more "closed" position. (See reference...) Figure 4A Multiple movable blades 90 can be moved to a relatively "closed" position, where, as indicated by arrow 96, the exhaust flow is moderately directed to the turbine 82, thereby affecting the enthalpy delivered to the turbine 82 at a lower exhaust mass flow rate and the associated power delivered to the compressor impeller 88 to achieve the target boost pressure. Alternatively, refer to Figure 4B The multiple movable blades 90 can be moved to a relatively "open" position, in which the exhaust flow is actively directed to the turbine 82, as indicated by arrow 98, thereby affecting the enthalpy delivered to the turbine 82 at a higher exhaust mass flow rate and the associated power delivered to the compressor impeller 88 to achieve the target boost pressure.

[0057] Reference Figure 5 The only way for air and fuel to enter and exit the combustion chamber 60 is through valves 100 and 106. Intake valve 100 opens and allows fuel and air to enter the combustion chamber 60, as indicated by arrow 102. After fuel and air enter the combustion chamber 60, intake valve 100 closes, sealing the combustion chamber 60. Spark plug 104 ignites the air-fuel mixture within the combustion chamber 60. After combustion, exhaust valve 106 opens and allows exhaust gas to exit from the combustion chamber 60, as indicated by arrow 108. A first spring 110 and intake camshaft 112 control the opening and closing of intake valve 100, and a second spring 114 and exhaust camshaft 116 control the opening and closing of exhaust valve 106 during engine operation.

[0058] In one exemplary embodiment, the vehicle engine 20 is adapted to control the exhaust gas temperature (EGT) at the inlet 118 of the catalyst 50. The engine 20 includes an EGT sensor 120 in communication with a system controller 122 adapted to measure the exhaust gas temperature at the inlet 118 of the catalyst 50.

[0059] System controller 122 is a non-general-purpose electronic control device having a pre-programmed digital computer or processor, memory or non-transitory computer-readable medium for storing data such as 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, compact 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 in which data can be permanently stored and media in which data can be stored and later rewritten, such as rewritable optical discs or erasable memory devices. Computer code includes any type of program code, including source code, object code, and executable code. System controller 122 may be vehicle controller 34, or alternatively, system controller 122 may be a separate controller that communicates with vehicle controller 34 and is dedicated to controlling engine-related functions.

[0060] System controller 122 is adapted to receive the temperature of the exhaust gas at the inlet 118 leading to catalyst 50 from an EGT sensor 120 disposed at the inlet 118 leading to catalyst 50, and compare the measured EGT with a target EGT. In an exemplary embodiment, system controller 122 uses a temperature model responsive to engine operating conditions to predict the temperature of the exhaust gas at the inlet 118 of catalyst 50. The target EGT is a predetermined temperature for optimal operation of engine 20 and related systems, and is a temperature that will not cause excessive degradation or damage to catalyst 50.

[0061] When the measured EGT is greater than the target EGT, the system controller 122 is adapted to restrict gas exchange within cylinders 54 of the engine 20 during the intake stroke and to increase the turbine efficiency of the variable geometry turbocharger 76 of the engine 20 by increasing the boost from the turbocharger 76. During the intake stroke, the exhaust valve 106 of cylinder 54 is closed and the intake valve 100 of cylinder 54 is open, allowing air and fuel to enter the combustion chamber 60 of cylinder 54. For the purposes described herein, the operation of the system controller 122 in restricting gas exchange will be described separately with respect to “cylinder 54”. Those skilled in the art will understand that restricting gas exchange can be applied to all or any part of a plurality of cylinders 54 within the engine 20.

[0062] In one exemplary embodiment, when limiting gas exchange within cylinder 54 during the intake stroke, system controller 122 is also adapted to prematurely close the intake valve 100 of cylinder 54 during the intake stroke, thereby reducing the volume of the air-fuel mixture received within cylinder 54 during the intake stroke. The intake valve 100 may comprise a single intake valve, or, as in some configurations, each cylinder 54 may comprise two separate intake valves that cooperate to allow air and fuel to enter cylinder 54 during the intake stroke. For the purposes discussed herein, engine 20 will be described as having a single intake valve 100 per cylinder 54. It should be understood that the novel features of this disclosure also apply to dual-intake-valve configurations, wherein the timing of one or both intake valves is altered to reduce the volume of the air-fuel mixture received within cylinder 54 during the intake stroke. The intake valve 100 is prematurely closed by actuating a cam phaser 124 that communicates with system controller 122. The cam phaser 124 is adapted to act on the intake camshaft 112 to change the position of the intake camshaft 112 and to change the opening and closing timing of the intake valve 100. The cam phaser can advance (open or close faster) or delay (open or close later) the opening and closing timing of the intake valve 100. In one exemplary embodiment, the cam phaser 124 is an electronically actuated electronic phaser (ePhaser). In another exemplary embodiment, the cam phaser 124 is a hydraulically actuated cam phaser. Those skilled in the art will understand that any type of cam phaser 124 can be used to change the opening and closing timing of the intake valve 100 within the scope of the novel features of this disclosure.

[0063] Prematurely closing the intake valve 100 to limit gas exchange within cylinder 54 is known as early intake valve closing (EIVC). In one exemplary embodiment, the intake camshaft 112 is a short-duration intake camshaft. Duration is simply the number of crankshaft angles by which the valve moves away from its valve seat (remains open). Air / fuel feed into or out of cylinder 54 whenever valves 100, 106 open. Generally, the longer valves 100, 106 remain open, the higher the engine 20 rotates (revolutions per minute, RPM). A longer duration means longer valves 100, 106 remain open, affecting power band and drive capability. A lower duration increases low-end torque, resulting in better idle quality but at the expense of top power. Short-duration camshafts also limit valve lift due to lifter rate limitations. A shorter duration enables EIVC.

[0064] In one exemplary embodiment, the system controller 122 is further adapted to adjust the spark timing within the cylinder 54 based on the advance of intake valve 100 closing. Ignition timing (from the spark plug 104) is typically advanced to the maximum braking torque (MBT) timing during light-load operation. Under higher loads, ignition timing is delayed to prevent knocking. When the engine is cold, ignition timing can be delayed, combined with delayed fuel injection and earlier exhaust valve opening, to allow the catalytic converter (catalyst 50) to reach operating temperature more quickly. EIVC alters the optimal ignition timing; therefore, spark timing can be adjusted accordingly in conjunction with EIVC.

[0065] Because a portion of the intake stroke cannot expel new charge, prematurely closing the intake valve 100 limits the filling of cylinder 54. This limits the volumetric efficiency of gas exchange. To overcome this low volumetric efficiency and maintain a constant engine load, increased boost is required from the variable geometry turbocharger 76. This increased boost requires more shaft 80 to drive the compressor impeller 88. Increased work is achieved by extracting increased enthalpy from the exhaust stream. The decrease in enthalpy in the exhaust stream reduces the exhaust temperature. Therefore, as the intake valve closing timing (EIVC) changes, the increased boost from the variable geometry turbocharger 76 can be used to control the exhaust temperature.

[0066] In one exemplary embodiment, the system controller 122 is adapted to selectively adjust the angle of each of the plurality of movable blades 90 to increase the boost from the variable geometry turbocharger. The variable geometry turbocharger 76 of this disclosure does not include an exhaust valve; therefore, all (100%) of the exhaust gas is directed through the turbine 82 of the variable geometry turbocharger 76, increasing the boost from the variable geometry turbocharger 76 and increasing the enthalpy extraction from the exhaust gas directed through the turbine 82 of the variable geometry turbocharger 76.

[0067] The variable geometry turbocharger 76 allows for increased boost, widening the range of exhaust temperature control. The variable geometry turbocharger 76 alters turbine efficiency, providing another control parameter for temperature control because it allows for the direct extraction of variable enthalpy from the exhaust stream. The design of the variable geometry turbocharger 76 results in all exhaust flow being directed through the turbine 82, maximizing enthalpy extraction and also ensuring good mixing of the exhaust, avoiding the possibility of hot spots forming on the catalyst 50 surface due to stratification. In addition to the volumetric efficiency effect of early intake valve closing, this process also leads to a reduction in the effective compression ratio. This reduces the knock sensitivity of the engine combustion system, allowing for earlier combustion phasing, which increases effective expansion, extracts more work during the expansion stroke, and thus generates lower temperatures at the end of the cycle. Therefore, increasing the efficiency at the variable geometry turbocharger 76 (providing more boost) enables the use of EIVC to reduce exhaust temperature and provides additional control parameters to provide further reductions in exhaust temperature. The result is a wider range of exhaust temperature control and a greater maximum capacity to extract enthalpy from the exhaust flow (when shaft 80 is operating), allowing for improved exhaust temperature reduction when needed.

[0068] In another exemplary embodiment, when the measured EGT is less than the target EGT, the system controller 122 is adapted to adjust gas exchange during the intake stroke within the cylinder 54 of the engine 20 to increase the EGT. Ideally, the exhaust temperature is equal to the target EGT. In some cases, the target EGT is defined by an upper target EGT and a lower target EGT, defining a window or range for the target EGT. Therefore, as described above, if the measured EGT is greater than the target EGT, or falls outside / above the target EGT range (above the upper target EGT), the system controller 122 will reduce the EGT via EIVC and increase the boost from the variable geometry turbocharger 76. Furthermore, if the measured EGT is less than the target EGT, or falls outside / below the target EGT range (below the lower target EGT), the system controller 122 will increase the EGT by adjusting (advancing / retarding) the closing timing of the intake valve 100 and by adjusting the boost from the variable geometry turbocharger 76 to increase the EGT.

[0069] In another exemplary embodiment, when the measured EGT equals the target EGT (falls within the range of the target EGT), the system controller is adapted to 1) maintain the current gas exchange calibration within cylinder 54, or 2) limit gas exchange within cylinder 54 during the intake stroke and increase the turbine efficiency of the variable geometry turbocharger 76 of engine 20 by increasing the boost from the variable geometry turbocharger 76. Even when the measured EGT equals the target EGT (falls within the range of the target EGT), under certain operating conditions, it may be desirable to reduce the exhaust temperature; therefore, the system controller may maintain the current calibration, maintain the EGT, or take steps to reduce the EGT, depending on the current operating conditions of engine 20.

[0070] Reference Figure 6 The method 200 for controlling the exhaust temperature within the vehicle engine 20 includes: starting at block 202, measuring the exhaust temperature (exhaust temperature, EGT) at the catalyst inlet 118 using an EGT sensor 120 communicating with a system controller 122; moving to block 204, comparing the measured EGT with a target EGT or a target EGT range using the system controller 122; moving to block 206, when the measured EGT is greater than the target EGT (above the upper target EGT); moving to block 208, limiting gas exchange within the cylinders 54 of the engine 20 during the intake stroke using the system controller 122; and moving to block 210, increasing the turbine efficiency of the variable geometry turbocharger 76 of the engine 20 by increasing boost from the variable geometry turbocharger 76 using the system controller 122.

[0071] In one exemplary embodiment, when the EGT measured at block 206 is not greater than the target EGT (above the upper target EGT), the method moves to block 212; when the measured EGT is less than the target EGT (below the lower target EGT), the method 200 includes moving to block 214 and using the system controller 122 to adjust the gas exchange during the intake stroke in the cylinder 54 within the engine 20 to increase the EGT.

[0072] In one exemplary embodiment, when the EGT measured at block 212 is not less than the target EGT (the measured EGT is equal to or falls within the target EGT range), method 200 includes one of the following: moving from block 212 to block 216 to maintain the current gas exchange calibration in cylinder 54 using system controller 122; moving from block 212 to block 218 to limit gas exchange in cylinder 54 during the intake stroke using system controller 122; and moving to block 220 to increase the turbine efficiency of the variable geometry turbocharger 76 of engine 20 by increasing the boost from the variable geometry turbocharger 76 using system controller 122.

[0073] In another exemplary embodiment, limiting gas exchange within cylinder 54 during the intake stroke using system controller 122 at blocks 208 and 218 further includes: using system controller 122 to prematurely close intake valve 100 of cylinder 54 during the intake stroke and reducing the volume of air-fuel mixture received within cylinder 54 during the intake stroke.

[0074] In another exemplary embodiment, at blocks 208 and 218, the early closing of the intake valve 100 for cylinder 54 by the system controller 122 during the intake stroke further includes adjusting the timing of the intake camshaft 112 associated with the intake valve 100 by means of a cam phaser 124 communicating with the system controller 122.

[0075] In another exemplary embodiment, adjusting the timing of the intake camshaft 112 associated with the intake valve 100 using the cam phaser 124 at blocks 208 and 218 further includes adjusting the timing of the intake camshaft 112 associated with the intake valve 100 for a short duration using the cam phaser 124.

[0076] In another exemplary embodiment, after limiting gas exchange within cylinders 54 of engine 20 during the intake stroke using system controller 122 at block 208, and increasing the turbine efficiency of variable geometry turbocharger 76 of engine 20 by increasing boost from variable geometry turbocharger 76 using system controller 122 at block 210, method 200 further includes moving to block 222 to adjust spark timing based on advance of intake valve 100 closing, and after limiting gas exchange within cylinders 54 of engine 20 during the intake stroke using system controller 122 at block 218, and increasing the turbine efficiency of variable geometry turbocharger 76 of engine 20 by increasing boost from variable geometry turbocharger 76 using system controller 122 at block 220, method 200 further includes moving to block 224 to adjust spark timing based on advance of intake valve 100 closing.

[0077] In another exemplary embodiment, increasing the boost from the variable geometry turbocharger 76 using the system controller 122 at blocks 210 and 220 further includes adjusting the angle of each of a plurality of movable blades 90 within a turbine 82, which is in communication with the system controller 122 and adapted to direct exhaust flow through the turbine 82 of the variable geometry turbocharger 76.

[0078] In another exemplary embodiment, the increased boost from the variable geometry turbocharger 76 at blocks 210 and 220 further includes directing all exhaust from the engine 20 through the turbine 82 of the variable geometry turbocharger 76.

[0079] In another exemplary embodiment, the increased boost from the variable geometry turbocharger 76 at blocks 210 and 220 further includes increasing the enthalpy extracted from the exhaust gas of the turbine 82 guided through the variable geometry turbocharger 76.

[0080] The benefits provided by the engine 20 and method 200 of this disclosure include, but are not limited to, improved robustness of exhaust system components by limiting exposure to high-temperature exhaust gases, improved emission control by limiting catalyst 50 aging, and allow for emission reductions using the same or fewer active catalytic materials. The use of EIVC eliminates cam profile switching across most of the engine 20's operating curve, reduces calibration complexity, and provides a means to limit improved exhaust temperature under heavy-load conditions (e.g., traction), which allows for the use of less enrichment for component protection, resulting in emissions and fuel consumption benefits. Compared to a twin-scroll turbocharger, the variable geometry turbocharger 76 enables higher power output from the engine 20 while improving emissions and flow distribution to the catalyst 50, further improving the temperature uniformity of the catalyst 50 and reducing the wetting area of ​​the variable geometry turbocharger 76, and also provides lower mass and increased enthalpy for heating the catalyst 50.

[0081] The description in this disclosure is exemplary in nature only, and variations thereof without departing from the spirit of this disclosure are intended to be within the scope of this disclosure. Such variations should not be considered as departing from the scheme and scope of this disclosure.

Claims

1. A method for controlling the exhaust temperature within a vehicle engine, comprising: The EGT at the catalyst inlet is measured using an exhaust temperature (EGT) sensor that communicates with the system controller. The measured EGT is compared with the target EGT using the system controller. as well as When the measured EGT is greater than the target EGT: During the intake stroke, the system controller restricts gas exchange within the cylinders of the engine; and The system controller is used to increase the turbine efficiency of the variable geometry turbocharger of the engine by increasing the boost pressure from the turbocharger.

2. The method of claim 1, further comprising, when the measured EGT is less than the target EGT, using the system controller to adjust the gas exchange during the intake stroke in the cylinder of the engine to increase the EGT.

3. The method of claim 2, wherein when the measured EGT equals the target EGT, it further comprises one of the following: The system controller is used to maintain the current gas exchange calibration within the cylinder; or The system controller is used to limit gas exchange within the cylinder during the intake stroke; and The system controller is used to increase the turbine efficiency of the variable geometry turbocharger of the engine by increasing the boost pressure from the turbocharger.

4. The method according to claim 3, wherein, Limiting gas exchange in the cylinder during the intake stroke using the system controller also includes using the system controller to close the intake valve for the cylinder in advance during the intake stroke and reduce the volume of the air-fuel mixture received in the cylinder during the intake stroke.

5. The method according to claim 4, wherein, The method of using the system controller to close the intake valve of the cylinder in advance during the intake stroke further includes: using a cam phaser in communication with the system controller to adjust the timing of the intake camshaft associated with the intake valve.

6. The method according to claim 5, wherein, Adjusting the timing of the intake cam associated with the intake valve using the cam phaser also includes adjusting the timing of a short-duration intake camshaft associated with the intake valve using the cam phaser.

7. The method of claim 4, further comprising adjusting spark timing based on the advance of the closing of the intake valve.

8. The method according to claim 4, wherein, Increasing boost from the variable geometry turbocharger using the system controller further includes using the system controller to adjust the angle of each of a plurality of movable blades surrounding the turbine, the movable blades being in communication with the system controller and adapted to control the exhaust flow through the turbine of the variable geometry turbocharger.

9. The method according to claim 8, wherein, The increase in boost from the variable geometry turbocharger also includes directing all exhaust from the engine through the turbine of the variable geometry turbocharger.

10. The method according to claim 9, wherein, The increase in boost from the variable geometry turbocharger also includes: increasing enthalpy extraction from the exhaust gas guided through the turbine of the variable geometry turbocharger.

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