System and method for mitigating cold start emissions via rotation of turbocharger turbine

Abstract

Systems and methods are provided for mitigating cold start emissions via rotation of a turbocharger turbine. A trigger signal is received from a trigger signal source. A first control signal is issued to a wastegate actuator to open the wastegate in response to the trigger signal. A second control signal is issued to the turbine shaft actuator to rotate a turbine of the turbocharger. Rotation of the turbine causes recirculation air to flow in a recirculation flow path that includes an exhaust manifold, the turbine, an exhaust wall system, and a wastegate. The exhaust wall system includes a turbine housing of the turbine, an exhaust wall disposed between the turbine and the wastegate, and an exhaust wall disposed between the turbine and the catalyst brick. At least a portion of the recirculation flow path is adjacent to one side of the catalyst brick. Heat is transferred from the recirculated air to the exhaust wall system and to the catalyst bricks via one side of the catalyst.

Description

Technical Field

[0001] The technical field generally relates to vehicles, and more specifically to systems and methods for mitigating cold-start emissions via the rotation of a turbocharger turbine. Background Technology

[0002] Vehicles with internal combustion engines generate exhaust gases as a byproduct of the combustion process. These vehicles typically rely on catalyst blocks in a catalytic converter to process the exhaust gases, which are then released from the vehicle as emissions. The catalyst blocks typically need to reach an operating temperature to effectively process the exhaust gases. This operating temperature is called the catalyst ignition temperature. The catalyst ignition temperature is typically located approximately midway between the temperature of maximum conversion efficiency, such as, for example, 300°C. The maximum conversion efficiency temperature can be, for example, 500°C. A cold start occurs when a vehicle is started after the engine has been off for several hours. During a cold start, the vehicle may emit excessive emissions until the catalyst blocks reach the catalyst ignition temperature.

[0003] Accordingly, it is desirable to provide systems and methods for mitigating cold-start emissions by generating heat through the rotation of a turbocharger turbine. Other desirable features and characteristics will become apparent from the accompanying drawings and the foregoing technical and background information, based on the following detailed description and the appended claims. Summary of the Invention

[0004] A method for mitigating cold-start emissions generated by a vehicle via the rotation of a turbocharger turbine includes: receiving a trigger signal from a trigger signal source at a controller; issuing a first control signal to a wastegate actuator by the controller in response to the trigger signal to open a wastegate; and issuing a second control signal to a turbine shaft actuator by the controller to rotate the turbocharger turbine, wherein the rotation of the turbine causes recirculated air to flow in a recirculation flow path including an exhaust manifold, a turbine, an exhaust wall system, and a wastegate, wherein: the exhaust wall system includes a turbine housing of the turbine, an exhaust wall disposed between the turbine and the wastegate, and an exhaust wall disposed between the turbine and a catalyst block; at least a portion of the recirculation flow path is adjacent to one side of the catalyst block; and heat is transferred from the recirculated air to the exhaust wall system and to the catalyst block via one side of the catalyst block.

[0005] In at least one embodiment, the controller sending a second control signal to the turbine shaft actuator to rotate the turbine includes the controller sending a second control signal to the turbine shaft actuator to rotate the turbine in reverse, the reverse rotation of the turbine causing the recirculation flow path to become a reverse recirculation flow path.

[0006] In at least one embodiment, recirculated air enters the turbine outlet, the recirculated air entering the turbine having a first temperature; the turbine's reverse rotation compresses the recirculated air; and the compressed recirculated air, having a second temperature greater than the first temperature, exits the turbine inlet.

[0007] In at least one embodiment, receiving a trigger signal at the controller includes receiving a vehicle opening signal; and issuing a first control signal from the controller to the exhaust valve actuator to open the exhaust valve includes issuing a first control signal from the controller to the exhaust valve actuator to partially open the exhaust valve.

[0008] In at least one embodiment, receiving a trigger signal at the controller includes receiving an engine start signal; and issuing a first control signal from the controller to the wastegate actuator to open the wastegate includes issuing a first control signal from the controller to the wastegate actuator to fully open the wastegate.

[0009] In at least one embodiment, the method further includes: generating a turbine rotational speed by a controller based on exhaust mass flow rate and exhaust temperature; and sending a second control signal from the controller to a turbine shaft actuator to cause the turbine to rotate in the opposite direction at the turbine rotational speed.

[0010] In at least one embodiment, receiving a trigger signal at the controller includes receiving a vehicle start signal; issuing a second control signal from the controller to the turbine shaft actuator to rotate the turbine includes issuing a second control signal from the controller to the turbine shaft actuator to rotate the turbine in the forward direction, the forward rotation of the turbine causing the recirculation flow path to become a forward recirculation flow path; and issuing a first control signal from the controller to the exhaust valve actuator to open the exhaust valve includes issuing a first control signal from the controller to the exhaust valve actuator to partially open the exhaust valve.

[0011] In at least one embodiment, the method further includes the controller issuing a third control signal to the compressor bypass valve actuator in response to a trigger signal to open the compressor bypass valve.

[0012] In at least one embodiment, a portion of the recirculated air passes through the catalyst brick.

[0013] In at least one embodiment, the turbine shaft actuator is an electric generator unit (MGU).

[0014] A system for mitigating cold-start emissions generated by a vehicle via rotation of a turbocharger turbine includes: at least one processor and at least one memory communicatively coupled to the at least one processor. The at least one memory includes instructions, when executed by the at least one processor, to cause the at least one processor to: receive a trigger signal from a trigger signal source; issue a first control signal to a wastegate actuator to open a wastegate in response to the trigger signal; and issue a second control signal to a turbine shaft actuator to rotate the turbocharger turbine, wherein the rotation of the turbine causes recirculated air to flow in a recirculation flow path including an exhaust manifold, a turbine, an exhaust wall system, and a wastegate, wherein: the exhaust wall system includes a turbine housing of the turbine, an exhaust wall disposed between the turbine and the wastegate, and an exhaust wall disposed between the turbine and a catalyst block; at least a portion of the recirculation flow path is adjacent to one side of the catalyst block; and heat is transferred from the recirculated air to the exhaust wall system and to the catalyst block via one side of the catalyst block.

[0015] In at least one embodiment, the at least one memory further includes instructions that, when executed by at least one processor, cause the at least one processor to perform the following operation: issue a second control signal to the turbine shaft actuator to reverse the rotation of the turbine, the reverse rotation of the turbine causing the recirculation flow path to become a reverse recirculation flow path.

[0016] In at least one embodiment, recirculated air enters the turbine outlet, the recirculated air entering the turbine having a first temperature; the turbine's reverse rotation compresses the recirculated air; and the compressed recirculated air, having a second temperature greater than the first temperature, exits the turbine inlet.

[0017] In at least one embodiment, the at least one memory further includes instructions, when executed by at least one processor, to cause the at least one processor to: receive a trigger signal, the trigger signal including a vehicle opening signal; and issue a first control signal to the exhaust valve actuator to partially open the exhaust valve.

[0018] In at least one embodiment, the at least one memory further includes instructions that, when executed by at least one processor, cause the at least one processor to: receive a trigger signal, the trigger signal including an engine start signal; and issue a first control signal to the exhaust valve actuator to fully open the exhaust valve.

[0019] In at least one embodiment, the at least one memory further includes instructions, when executed by at least one processor, to cause the at least one processor to perform the following operations: generate a turbine speed based on exhaust mass flow rate and exhaust temperature; and issue a second control signal to a turbine shaft actuator to cause the turbine to rotate in the opposite direction at the turbine speed.

[0020] In at least one embodiment, the at least one memory further includes instructions, when executed by at least one processor, to cause the at least one processor to: receive a trigger signal, the trigger signal including a vehicle opening signal; issue a second control signal to a turbine shaft actuator to cause the turbine to rotate forward, the forward rotation of the turbine causing the recirculation flow path to become a forward recirculation flow path; and issue a first control signal to an exhaust valve actuator to partially open the exhaust valve.

[0021] In at least one embodiment, the at least one memory further includes instructions that, when executed by at least one processor, cause the at least one processor to perform the following operation: in response to a trigger signal, send a third control signal to the compressor bypass valve actuator to open the compressor bypass valve.

[0022] In at least one embodiment, a portion of the recirculated air passes through the catalyst brick.

[0023] A vehicle including a system for mitigating cold-start emissions generated by a vehicle via rotation of a turbocharger turbine includes: at least one processor; and at least one memory communicatively coupled to the at least one processor. The at least one memory includes instructions, when executed by the at least one processor, to cause the at least one processor to: receive a trigger signal from a trigger signal source; issue a first control signal to a wastegate actuator to open a wastegate in response to the trigger signal; and issue a second control signal to a turbine shaft actuator to rotate the turbocharger turbine, wherein the rotation of the turbine causes recirculated air to flow in a recirculation flow path including an exhaust manifold, a turbine, an exhaust wall system, and a wastegate, wherein: the exhaust wall system includes a turbine housing of the turbine, an exhaust wall disposed between the turbine and the wastegate, and an exhaust wall disposed between the turbine and a catalyst block; at least a portion of the recirculation flow path is adjacent to one side of the catalyst block; and heat is transferred from the recirculated air to the exhaust wall system and via one side of the catalyst block to the catalyst block. Attached Figure Description

[0024] Exemplary embodiments will now be described in conjunction with the following figures, wherein the same numerals denote the same elements, and wherein:

[0025] Figure 1 This is a functional block diagram of a vehicle including a cold start emission mitigation system according to at least one embodiment;

[0026] Figure 2 This is a functional block diagram of a controller including a cold start emission mitigation system according to at least one embodiment;

[0027] Figure 3 It is a functional block diagram of an internal combustion engine system according to at least one embodiment; and

[0028] Figure 4 This is a flowchart representation of an exemplary method for mitigating cold start emissions via the reverse rotation of a turbine after the vehicle is started and before the engine is started, according to at least one embodiment;

[0029] Figure 5 This is a flowchart representation of an exemplary method for mitigating cold start emissions via forward rotation of a turbine after the vehicle is started and before the engine is started, according to at least one embodiment;

[0030] Figure 6 This is a flowchart representation of an exemplary method for mitigating cold-start emissions by reversing the rotation of a turbine after the engine has been started, according to at least one embodiment. Detailed Implementation

[0031] The following detailed description is merely exemplary in nature and is not intended to limit application and use. Furthermore, it is not intended to be bound by any express or implied theory presented in the foregoing technical field, background art, summary of the invention, or the following detailed description. As used herein, the term module refers to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (shared, dedicated, or grouped) and memory executing one or more software or firmware programs, combinational logic circuitry, and / or other suitable components providing the described functionality.

[0032] This document describes embodiments of the present disclosure in terms of functional and / or logical block components and various processing steps. It should be understood that such block components can be implemented by any number of hardware, software, and / or firmware components configured to perform specified functions. For example, embodiments of the present disclosure can employ various integrated circuit components, such as memory elements, digital signal processing elements, logic elements, lookup tables, etc., which can perform various functions under the control of one or more microprocessors or other control devices. Furthermore, those skilled in the art will understand that embodiments of the present disclosure can be practiced in combination with any number of systems, and the systems described herein are merely exemplary embodiments of the present disclosure.

[0033] For the sake of brevity, conventional techniques related to signal processing, data transmission, signaling, control, and other functional aspects of the system (and its various operating components) are not described in detail herein. Furthermore, the connecting lines shown in the various figures included herein are intended to illustrate exemplary functional relationships and / or physical couplings between various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in the embodiments of this disclosure.

[0034] refer to Figure 1This diagram illustrates a functional block diagram of a vehicle including a cold start emissions mitigation system 100 according to at least one embodiment. The vehicle 10 typically includes a chassis 12, a body 14, front wheels 16, and rear wheels 18. While the vehicle 10 is described as a passenger car in the illustrated embodiment, it can be other types of vehicles, including trucks, sport utility vehicles (SUVs), and recreational vehicles (RVs).

[0035] In various embodiments, the body 14 is arranged 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 wheels 16 and 18 are rotatably coupled to the chassis 12 near respective corners of the body 14.

[0036] In various embodiments, vehicle 10 is an autonomous or semi-autonomous vehicle that is automatically controlled to transport passengers and / or goods from one place to another. For example, in an exemplary embodiment, vehicle 10 is a so-called Level 2, Level 3, Level 4, or Level 5 automation system. Level 2 automation means that the vehicle assists the driver in various driving tasks under the supervision of the driver. Level 3 automation means that the vehicle can take over all driving functions in certain situations. All major functions are automatic, including braking, steering, and acceleration. At this level, the driver can completely let go until the vehicle otherwise informs the driver. Level 4 system indicates “high automation”, referring to the driving mode-specific performance of the automated driving system for all aspects of dynamic driving tasks, even if the human driver does not respond appropriately to intervention requests. Level 5 system indicates “full automation”, referring to the full-time performance of the automated driving system for all aspects of dynamic driving tasks under all roadway and environmental conditions that can be managed by a human driver.

[0037] 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, at least one controller 34, and a communication system 36. The controller 34 is configured to implement an automated driving system (ADS). The propulsion system 20 is configured to generate power to propel the vehicle. The propulsion system 20 includes an internal combustion engine (ICE). In various embodiments, the propulsion system 20 may also include an electric motor such as a traction motor, a fuel cell propulsion system, and / or any other type of propulsion configuration. The transmission system 22 is configured to transmit power from the propulsion system 20 to the wheels 16, 18 according to a selectable speed ratio. According to various embodiments, the transmission system 22 may include a step-ratio automatic transmission, a continuously variable transmission (CVT), or other suitable transmission. The braking system 26 is configured to provide braking torque to the wheels 16, 18. In various embodiments, the braking system 26 may include a friction brake, a brake-by-wire brake, a regenerative braking system such as an electric motor, and / or other suitable braking systems.

[0038] Steering system 24 is configured to influence the positioning of wheels 16. Although depicted for illustrative purposes as including a steering wheel and steering column, in some embodiments contemplated within the scope of this disclosure, steering system 24 may not include a steering wheel and / or steering column. Steering system 24 includes a steering column coupled to axle 50 associated with the front wheels 16 via, for example, a rack and pinion or other mechanism (not shown). Alternatively, steering system 24 may include a steer-by-wire system comprising an actuator associated with each of the front wheels 16.

[0039] The sensor system 28 includes one or more sensing devices 40a-40n that sense observable conditions of the external and / or internal environments of the vehicle 10. The sensing devices 40a-40n may include, but are not limited to, radar, lidar, global positioning system, optical camera, thermal imager, ultrasonic sensor, steering wheel sensor, and / or other sensors.

[0040] The vehicle dynamics sensor provides vehicle dynamics data including longitudinal velocity, yaw rate, lateral acceleration, and longitudinal acceleration. The vehicle dynamics sensor may include wheel sensors that measure information relating to one or more wheels of the vehicle 10. In one embodiment, the wheel sensors include wheel velocity sensors coupled to each of the wheels 16, 18 of the vehicle 10. Furthermore, the vehicle dynamics sensor may include one or more accelerometers (provided as part of an inertial measurement unit (IMU)) that measure information relating to the acceleration of the vehicle 10. In various embodiments, the accelerometers measure one or more acceleration values ​​of the vehicle 10, including lateral and longitudinal acceleration and yaw rate. In at least one embodiment, the vehicle dynamics sensor provides vehicle movement data.

[0041] Actuator system 30 includes one or more actuator devices 42a-42n that control one or more vehicle features, such as, but not limited to, one or more wheels 16, 18, propulsion system 20, transmission system 22, steering system 24, and braking system 26. In various embodiments, vehicle features may also include interior and / or exterior vehicle features, such as, but not limited to, doors, trunk, and cabin features, such as air, music, lighting, etc. (not numbered).

[0042] Communication system 36 is configured to wirelessly communicate information to and from other entities, such as, but not limited to, other vehicles (“V2V” communication), infrastructure (“V2I” communication), remote systems, and / or personal devices. In an exemplary embodiment, communication system 36 is a wireless communication system configured to communicate via a wireless local area network (WLAN) using the IEEE 802.11 standard or by using cellular data communication. However, additional or alternative communication methods (such as dedicated short-range communication (DSRC) channels) are also considered to be within the scope of this disclosure. A DSRC channel refers to a one-way or two-way short-to-medium-range wireless communication channel specifically designed for automotive use and with a corresponding set of protocols and standards.

[0043] Data storage device 32 stores data for use in the ADS of vehicle 10. In various embodiments, data storage device 32 stores a defined map of the navigable environment. In various embodiments, the defined map may be predefined by and obtained from a remote system. For example, the defined map may be assembled by a remote system and communicated to vehicle 10 (wirelessly and / or via wire) and stored in data storage device 32. It is understood that data storage device 32 may be part of controller 34, separate from controller 34, or part of controller 34 and a separate system.

[0044] The controller 34 includes at least one processor 44 and a computer-readable storage device or medium 46. The processor 44 may be any custom or commercially available processor, central processing unit (CPU), graphics processing unit (GPU), auxiliary processor among several processors associated with the controller 34, semiconductor-based microprocessor (in the form of a microchip or chipset), macroprocessor, any combination thereof, or any device generally used for executing instructions. The computer-readable storage device or medium 46 may include 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 that can be used to store various operational variables when the processor 44 is powered off. The computer-readable storage device or medium 46 may be implemented using any of several 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 represent executable instructions used by the controller 34 to control the vehicle 10). In at least one embodiment, computer-readable storage device 46 is a memory configured to store at least one memory of cold start emission mitigation system 100.

[0045] The instructions may include one or more separate programs, each comprising an ordered list of executable instructions for implementing logical functions. When executed by processor 44, the instructions receive and process signals from sensor system 28, execute logic, calculations, methods, and / or algorithms for automatically controlling components of vehicle 10, and generate control signals to actuator system 30 based on the logic, calculations, methods, and / or algorithms to automatically control components of 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, perform logic, calculations, methods and / or algorithms, and generate control signals to automatically control the features of vehicle 10. In various embodiments, the controllers(s) 34 are configured to implement ADS.

[0046] refer to Figure 2A functional block diagram of a controller 34 including a cold start emission mitigation system 100 according to at least one embodiment is shown. The controller 34 includes at least one processor 44 and at least one memory 46. The at least one processor 44 is a programmable device including one or more instructions stored in or associated with the at least one memory 46. The at least one memory 46 includes instructions that the at least one processor 44 is configured to execute. The at least one memory 46 includes embodiments of the cold start emission mitigation system 100 configured to mitigate cold start emissions by managing turbocharger turbine rotation. In at least one embodiment, the cold start emission mitigation system 100 is configured to mitigate cold start emissions by managing turbocharger turbine rotation prior to a fuel injection or combustion event. In one instance, turbocharger rotation occurs before the engine actually has any cylinder fill event. The controller 34 is configured to communicatively couple to a trigger signal source 200, a turbine shaft actuator 202, one or more oxygen sensors 204, a wastegate actuator 206, and a compressor bypass valve actuator 208. In at least one embodiment, the trigger signal source 200 is configured to generate a vehicle start signal when the vehicle 10 is started. In at least one embodiment, the trigger signal source 200 is configured to generate an engine start signal when the engine is started. The controller 34 may include additional components to facilitate the operation of the cold start emission mitigation system 100.

[0047] refer to Figure 3 A functional block diagram of an internal combustion engine system 300 according to at least one embodiment is shown. The internal combustion engine system 300 includes a turbocharger 302, an engine 304, a wastegate 306, a compressor bypass valve 308, and a catalyst block 310. The turbocharger 302 includes a compressor 312, a turbine 314, a turbine shaft 316, and a turbine shaft actuator 202. The wastegate 306 includes a wastegate actuator 206. The compressor bypass valve 308 includes a compressor bypass valve actuator 208. The catalyst block 310 is associated with one or more oxygen sensors 204. The catalyst ignition temperature is determined based on oxygen sensor data received from the oxygen sensors 204. The conversion of exhaust hydrocarbons and nitrogen oxides is determined via oxygen content. In at least one embodiment, the turbine shaft actuator 202 is an electric generator unit (MGU).

[0048] The internal combustion engine system 300 includes an intake manifold 316 and an exhaust manifold 318. The intake manifold 316 couples the outlet fluid of the compressor 312 to the intake valves of the cylinders of the engine 304. The exhaust manifold 318 couples the exhaust valve fluid of the cylinders of the engine 304 to the inlet of the turbine 314. The internal combustion engine system 300 may include additional components to facilitate the operation of the internal combustion engine system 300.

[0049] During normal engine operation, compressor 312 draws in ambient air and generates compressed air. Engine 304 receives the compressed air from compressor 312 via intake manifold 316. Fuel is injected into engine 304. The compressed air and fuel combine to form an air-fuel mixture used during combustion in engine 304. Exhaust gas is generated by engine 304 as a byproduct of the combustion process. During combustion, the exhaust gas generated by engine 304 flows through exhaust manifold 318 to the inlet of turbine 314. As the exhaust gas passes through turbine 314, it causes turbine 314 to rotate. The exhaust gas flows through turbine 314 and exits via turbine 314 outlet, passing through catalyst block 310 before being released from vehicle 10 as emissions.

[0050] Before releasing exhaust gas as emissions from vehicle 10, vehicle 10 relies on catalyst brick 310 to process the exhaust gas generated by the combustion process. Catalyst brick 310 typically needs to reach an operating temperature to effectively process the exhaust gas. This operating temperature is called the catalyst ignition temperature. The catalyst ignition temperature is typically located approximately midway from the maximum conversion efficiency temperature, such as, for example, 300°C. The maximum conversion efficiency temperature can be, for example, 500°C. A cold start occurs when the vehicle is started after the engine 304 has been off for several hours. During a cold start, vehicle 10 may emit excessive emissions until catalyst brick 310 reaches its catalyst ignition temperature. Cold start emission mitigation system 100 is configured to manage the rotation of turbine 314 via turbine shaft actuator 202 to accelerate the process of catalyst brick 310 reaching its catalyst ignition temperature, thereby mitigating cold start emissions. Cold start emission mitigation system 100 manages the rotation of turbine 314 to allow recirculated air to flow in the recirculation flow path. The recirculation flow path includes an exhaust manifold 318, a turbine 314, an exhaust wall system, and a wastegate 306. The exhaust wall system includes the turbine housing, an exhaust wall disposed between the turbine and the wastegate, and an exhaust wall disposed between the turbine and the catalyst block. Heat is transferred from the recirculated air to the exhaust wall system and via the side of the catalyst block 310 facing the recirculation flow path to the catalyst block 310. Heating of the exhaust wall system facilitates catalyst ignition. The operation of an embodiment of the cold start emission mitigation system 100 will be described in more detail below.

[0051] refer to Figure 4 A flowchart representation of an exemplary method 400 for mitigating cold-start emissions via the reverse rotation of turbine 314 after the vehicle is started and before the engine is started, according to at least one embodiment, is shown. Method 400 will be described with reference to exemplary implementations of embodiments of cold-start emission mitigation system 100. As will be understood from this disclosure, the order of operations within method 400 is not limited to... Figure 4The execution may not be performed in the order shown, but may be performed in one or more different orders as applicable and in accordance with this disclosure.

[0052] At 402, the cold start emission mitigation system 100 receives a trigger signal from the trigger signal source 200 of the vehicle 10. The trigger signal is a vehicle start signal. In at least one embodiment, the trigger signal source 200 is a vehicle start button. The vehicle start button starts the vehicle 10 but does not start the engine 304 of the vehicle 10. At 404, the cold start emission mitigation system 100 commands the exhaust valve actuator 206 to partially open the exhaust valve 306. During reverse rotation, the turbine 314 may experience turbine-side surge. The opening of the exhaust valve is controlled to suppress turbine-side surge. To limit turbine-side surge, the exhaust valve 306 is not closed too much.

[0053] At 406, the cold start emission mitigation system 100 commands the turbine shaft actuator 202 to reverse the rotation of the turbine 314. In at least one embodiment, the turbine shaft actuator 202 is an electric generator unit (MGU). The MGU reverses the rotation of the turbine 314 in response to the command from the cold start emission mitigation system 100.

[0054] The reverse rotation of turbine 314 causes recirculated air to flow in a reverse recirculation flow path. The reverse recirculation flow path includes exhaust manifold 318, wastegate 306, exhaust wall system, and turbine 314. When turbine 314 rotates in reverse, it operates as a compressor. The reverse rotation of turbine 314 causes recirculated air to flow from exhaust manifold 318 through wastegate 306 and the exhaust wall system to the outlet of turbine 314, and out through the inlet of turbine 314. The recirculated air flowing from exhaust manifold 318 to the outlet of turbine 314 is the air retained in exhaust manifold 318 after engine 304 was previously shut down. In at least one embodiment, when the engine was previously shut down, additional air can flow from intake manifold 316 through engine 304 via exhaust manifold 318 to the outlet of turbine 314 due to the overlap of certain intake valves in certain cylinders of engine 304 with respect to their associated exhaust valves in a state of at least partial opening. This additional air becomes part of the recirculated air.

[0055] The reverse rotation of turbine 314 causes recirculated air to enter the outlet of turbine 314 and exit through the inlet of turbine 314. Because the reverse rotation of turbine 314 causes it to operate as a compressor, the recirculated air flowing into the outlet of turbine 314 is compressed as it flows out through the inlet of turbine 314. The recirculated air entering the outlet of turbine 314 has a first temperature. The compressed recirculated air leaving the inlet of turbine 314 has a second temperature. The second temperature is greater than the first temperature. The compressed recirculated air leaving turbine 314 is heated recirculated air, which is hotter than the recirculated air entering turbine 314.

[0056] Heated recirculated air exits the inlet of turbine 314 and flows to the exhaust wall system via exhaust manifold 318 and wastegate 306. Heat is transferred from the heated recirculated air to the exhaust wall system, thereby heating the exhaust wall system. One side of catalyst brick 310 faces the reverse recirculation flow path of the recirculated air. Heated recirculated air contacts this side of catalyst brick 310, and heat is transferred from the heated recirculated air to catalyst brick 310. The heated recirculated air expands as it flows, and a portion of the heated recirculated air flows from the exhaust wall system through catalyst brick 310. As the heated recirculated air flows through catalyst brick 310, heat from the heated recirculated air is transferred to catalyst brick 310. The recirculated air is heated by continuously passing through turbine 314, which performs compression work on the recirculated air.

[0057] Because the exhaust wall system and catalyst brick 310 are heated by heated recirculated air before the engine 304 is started, the catalyst brick 310 will take less time to reach the catalytic ignition temperature once the engine 304 is started and normal engine operation is initiated. Emissions generated after using the emission mitigation system 100 to heat the exhaust wall system and catalyst brick 310 before a cold start are lower than those generated during a cold start without the emission mitigation system 100. The reverse rotation of the turbine 314 generates heat within the exhaust system due to localized air movement and compression within the exhaust recirculation flow path. The reverse rotation of the turbine 314 allows the compressor 312 to act as a turbine. When the compressor 312 functions like a turbine, surge is less likely to occur. The turbine 314 will function like a compressor and is therefore susceptible to surge, but the turbine 314 and the exhaust system are more robust to surge than the compressor 312.

[0058] In at least one embodiment, when the cold start emission mitigation system 100 commands the exhaust valve actuator 206 at 404 to partially open the exhaust valve 306, the partial opening of the exhaust valve 306 is sufficient to further compress the recirculated air flowing in the reverse recirculation flow path, while ensuring that the pressure exerted on the turbine 314 by the recirculated air does not damage the turbine 314. The additional compression of the recirculated air is used to further heat the recirculated air.

[0059] At 408, the cold start emission mitigation system 100 commands the compressor bypass valve actuator 208 to open the compressor bypass valve 308. Reverse rotation of the turbine 314, achieved via the turbine shaft actuator 202, causes the compressor 312 to rotate in reverse. This reverse rotation of the compressor 312 causes it to operate as a turbine. The reverse rotation of the compressor 312 causes air from the intake manifold 316 to flow to the outlet of the compressor 312, exiting via the inlet of the compressor 312, flowing through the compressor bypass valve 308, and returning to the outlet of the compressor 312 via the intake manifold 316. The air flowing from the intake manifold 316 to the outlet of the compressor 312 is the air retained in the intake manifold 316 after the engine 304 was previously shut down. The compressor bypass valve 308 is opened to reduce the pressure caused by the airflow through the compressor 312 and to prevent damage to the compressor 312.

[0060] refer to Figure 5 A flowchart representation of an exemplary method 500 for mitigating cold-start emissions via forward rotation of a turbine after the vehicle is started and before the engine is started, according to at least one embodiment, is shown. Method 500 will be described with reference to exemplary implementations of embodiments of a cold-start emissions mitigation system 100. As will be understood from this disclosure, the order of operations within method 500 is not limited to... Figure 5 The execution may not be performed in the order shown, but may be performed in one or more different orders as applicable and in accordance with this disclosure.

[0061] At 502, the cold start emission mitigation system 100 receives a trigger signal from the trigger signal source 200 of the vehicle 10. The trigger signal is a vehicle start signal. In at least one embodiment, the trigger signal source 200 is a vehicle start button. The vehicle start button starts the vehicle 10 but does not start the engine 304 of the vehicle 10. At 504, the cold start emission mitigation system 100 commands the exhaust valve actuator 206 to partially open the exhaust valve 306.

[0062] At 506, the cold start emission mitigation system 100 commands the turbine shaft actuator 202 to rotate the turbine 314 in the forward direction. In at least one embodiment, the turbine shaft actuator 202 is an electric generator unit (MGU). The MGU responds to the command from the cold start emission mitigation system 100 to rotate the turbine 314 in the forward direction.

[0063] The forward rotation of turbine 314 causes recirculated air to flow in a forward recirculation flow path. This forward recirculation flow path includes exhaust manifold 318, turbine 314, exhaust wall system, and wastegate 306. When turbine 314 rotates forward, it operates as a turbine. The forward rotation of turbine 314 causes recirculated air to flow from exhaust manifold 318 to the inlet of turbine 314, exit through the outlet of turbine 314, pass through wastegate 306, and return to the inlet of turbine 314 via exhaust manifold 318. The recirculated air flowing from exhaust manifold 318 to the inlet of turbine 314 is the air retained in exhaust manifold 318 after engine 304 was previously shut down. In at least one embodiment, when the engine is previously shut down, additional air can flow from the intake manifold 316 through the engine 304 via the exhaust manifold 318 to the inlet of the turbine 314 due to the overlap of certain intake valves in certain cylinders of the engine 304 with respect to their associated exhaust valves in a state that is at least partially open. This additional air becomes part of the recirculated air.

[0064] The forward rotation of turbine 314 causes recirculated air to enter through the inlet of turbine 314 and exit through the outlet of turbine 314. The recirculated air entering the inlet of turbine 314 has a first temperature. The recirculated air exiting the outlet of turbine 314 has a second temperature. The second temperature is greater than the first temperature. The recirculated air exiting turbine 314 is heated recirculated air, which is hotter than the recirculated air entering turbine 314.

[0065] Recirculated air exits the turbine 314 outlet and flows through the exhaust wall system. Heat is transferred from the heated recirculated air to the exhaust wall system, thereby heating the exhaust wall system. One side of the catalyst brick 310 faces the forward recirculation flow path of the recirculated air. The heated recirculated air contacts this side of the catalyst brick 310, and heat is transferred from the heated recirculated air to the catalyst brick 310. The heated recirculated air expands as it flows, and a portion of the heated recirculated air flows from the exhaust wall system through the catalyst brick 310. As the heated recirculated air flows through the catalyst brick 310, heat from the heated recirculated air is transferred to the catalyst brick 310.

[0066] Because the exhaust wall system and catalyst brick 310 are heated by heated recirculated air before the engine 304 is started, the catalyst brick 310 will take less time to reach the catalytic ignition temperature once the engine 304 is started and normal engine operation is initiated. Normal engine operation indicates the occurrence of a cylinder ignition event. Emissions generated after using the emission reduction system 100 to heat the exhaust wall system and catalyst brick 310 before a cold start are lower than those generated during a cold start without using the emission reduction system 100.

[0067] In at least one embodiment, when the cold start emission mitigation system 100 commands the exhaust valve actuator 206 at 504 to partially open the exhaust valve 306, the amount of partial opening of the exhaust valve 306 is sufficient to compress the recirculated air flowing in the forward recirculation flow path, while ensuring that the pressure exerted on the turbine 314 by the recirculated air does not damage the turbine 314. The compression of the recirculated air is used to further heat the recirculated air.

[0068] At 508, the cold start emission mitigation system 100 commands the compressor bypass valve actuator 208 to open the compressor bypass valve 308. Forward rotation of the turbine 314, achieved via the turbine shaft actuator 202, causes forward rotation of the compressor 312.

[0069] The forward rotation of compressor 312 causes air from intake manifold 316 to flow through compressor bypass valve 308 to the inlet of compressor 312 and exit through the outlet of compressor 312. The air flowing from intake manifold 316 to the inlet of compressor 312 via compressor bypass valve 308 is the air retained in intake manifold 316 after engine 304 was previously shut down. Compressor bypass valve 308 is opened to reduce the pressure caused by the airflow through compressor 312 and to prevent damage to compressor 312. The recirculation of airflow through intake manifold 316, compressor bypass valve 306, and compressor 312 heats the components on the intake side of internal combustion engine system 300 before engine startup.

[0070] refer to Figure 6 A flowchart representation of an exemplary method 600 for mitigating cold-start emissions via the reverse rotation of turbine 314 after engine start-up, according to at least one embodiment, is shown. Method 600 will be described with reference to exemplary implementations of embodiments of cold-start emission mitigation system 100. As will be understood from this disclosure, the order of operations within method 600 is not limited to... Figure 6 The execution may not be performed in the order shown, but may be performed in one or more different orders as applicable and in accordance with this disclosure.

[0071] At 602, the cold start emission mitigation system 100 receives a trigger signal from the trigger signal source 200 of the vehicle 10. The trigger signal is an engine start signal. The engine start signal indicates the presence of a cylinder ignition event. In at least one embodiment, the trigger signal source 200 is an ignition switch. The ignition switch starts the engine 304 of the vehicle 10. At 604, the cold start emission mitigation system 100 commands the exhaust valve actuator 206 to fully open the exhaust valve 306.

[0072] At 606, the cold start emission mitigation system 100 commands the turbine shaft actuator 202 to reverse the rotation of the turbine 314 at the turbine speed. In at least one embodiment, the turbine shaft actuator 202 is an electric generator unit (MGU). The MGU reverses the rotation of the turbine 314 in response to the command from the cold start emission mitigation system 100. The cold start emission mitigation system 100 generates the turbine speed based on exhaust mass flow rate and exhaust temperature.

[0073] The reverse rotation of turbine 314 causes recirculated air to flow in a reverse recirculation flow path. This reverse recirculation flow path includes exhaust manifold 318, wastegate 306, exhaust wall system, and turbine 314. When turbine 314 rotates in reverse, it operates as a compressor. The reverse rotation of turbine 314 causes recirculated air to flow from exhaust manifold 318 through wastegate 306 and the exhaust wall system to the outlet of turbine 314, and then out through the inlet of turbine 314.

[0074] The reverse rotation of turbine 314 causes recirculated air to enter the outlet of turbine 314 and exit through the inlet of turbine 314. Because the reverse rotation of turbine 314 causes it to operate as a compressor, the recirculated air flowing into the outlet of turbine 314 is compressed as it flows out through the inlet of turbine 314. The recirculated air entering the outlet of turbine 314 has a first temperature. The compressed recirculated air leaving the inlet of turbine 314 has a second temperature. The second temperature is greater than the first temperature. The compressed recirculated air leaving turbine 314 is heated recirculated air, which is hotter than the recirculated air entering turbine 314.

[0075] Heated recirculated air exits the inlet of turbine 314 and flows through exhaust manifold 318 and wastegate 306 to the exhaust wall system. Heat is transferred from the heated recirculated air to the exhaust wall system, thereby heating the exhaust wall system. The exhaust wall system extends from the outlet of turbine 314 to catalyst brick 310. One side of catalyst brick 310 faces the reverse recirculation flow path of the recirculated air. Heated recirculated air contacts this side of catalyst brick 310, and heat is transferred from the heated recirculated air to catalyst brick 310. The heated recirculated air expands as it flows, and a portion of the heated recirculated air flows from the exhaust wall system through catalyst brick 310. As the heated recirculated air flows through catalyst brick 310, heat from the heated recirculated air is transferred to catalyst brick 310.

[0076] At 608, the cold start emission mitigation system 100 commands the compressor bypass valve actuator 208 to open the compressor bypass valve 308. Reverse rotation of the turbine 314, achieved via the turbine shaft actuator 202, causes reverse rotation of the compressor 312. This reverse rotation of the compressor 312 causes it to operate as a turbine. The reverse rotation of the compressor 312 causes air from the intake manifold 316 to flow to the outlet of the compressor 312, exit via the inlet of the compressor 312, flow through the compressor bypass valve 308, and return to the outlet of the compressor 312 via the intake manifold 316. The compressor bypass valve 308 is opened to reduce the pressure caused by the airflow through the compressor 312 and to prevent damage to the compressor 312. In at least one embodiment, normal operation of the internal combustion engine system 300 is restored at some point after the heating method is implemented.

[0077] While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiments or multiple exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of this disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing the exemplary embodiments or multiple exemplary embodiments. It should be understood that various changes can be made to the function and arrangement of the elements without departing from the scope of this disclosure as set forth in the appended claims and their legal equivalents.

Claims

1. A method for reducing cold-start emissions in a vehicle via the rotation of a turbocharger turbine, comprising: The controller receives the trigger signal from the trigger signal source. The controller, in response to the trigger signal, sends a first control signal to the exhaust valve actuator to open the exhaust valve; as well as The controller sends a second control signal to the turbine shaft actuator to rotate the turbocharger turbine, wherein the rotation of the turbine causes recirculated air to flow in a recirculation flow path, the recirculation flow path including an exhaust manifold, the turbine, an exhaust wall system, and the wastegate, wherein: The exhaust wall system includes the turbine housing of the turbine, an exhaust wall disposed between the turbine and the exhaust valve, and an exhaust wall disposed between the turbine and the catalyst block; At least a portion of the recirculation flow path is adjacent to one side of the catalyst brick; as well as Heat is transferred from the recirculated air to the exhaust wall system and via one side of the catalyst brick to the catalyst brick.

2. The method of claim 1, wherein the controller sends the second control signal to the turbine shaft actuator to rotate the turbine, which includes the controller sending the second control signal to the turbine shaft actuator to rotate the turbine in reverse, the reverse rotation of the turbine causing the recirculation flow path to become a reverse recirculation flow path.

3. The method according to claim 2, wherein: The recirculated air enters the outlet of the turbine, and the recirculated air entering the turbine has a first temperature; The reverse rotation of the turbine compresses the recirculated air; as well as Compressed recirculated air with a second temperature, which is greater than the first temperature, exits the turbine inlet.

4. The method according to claim 2, wherein: Receiving the trigger signal at the controller includes receiving a vehicle start signal; and Sending the first control signal from the controller to the exhaust valve actuator to open the exhaust valve includes sending the first control signal from the controller to the exhaust valve actuator to partially open the exhaust valve.

5. The method according to claim 2, wherein: Receiving the trigger signal at the controller includes receiving an engine start signal; and Sending the first control signal from the controller to the exhaust valve actuator to open the exhaust valve includes sending the first control signal from the controller to the exhaust valve actuator to fully open the exhaust valve.

6. The method according to claim 1, further comprising: The controller generates the turbine speed based on the exhaust mass flow rate and exhaust temperature; as well as The controller sends a second control signal to the turbine shaft actuator to cause the turbine to rotate in the opposite direction at the turbine speed.

7. The method according to claim 1, wherein: Receiving the trigger signal at the controller includes receiving a vehicle start signal; Sending the second control signal from the controller to the turbine shaft actuator to rotate the turbine includes sending the second control signal from the controller to the turbine shaft actuator to rotate the turbine in the forward direction, the forward rotation of the turbine causing the recirculation flow path to become a forward recirculation flow path; and Sending the first control signal from the controller to the exhaust valve actuator to open the exhaust valve includes sending the first control signal from the controller to the exhaust valve actuator to partially open the exhaust valve.

8. The method of claim 1, further comprising the controller issuing a third control signal to the compressor bypass valve actuator in response to the trigger signal to open the compressor bypass valve.

9. The method of claim 1, wherein a portion of the recirculated air passes through the catalyst brick.

10. A system for mitigating cold-start emissions generated by a vehicle via the rotation of a turbocharger turbine, comprising: At least one processor; as well as At least one memory, communicatively coupled to the at least one processor, the at least one memory including instructions that, when executed by the at least one processor, cause the at least one processor to perform the following operations: Receive trigger signal from trigger signal source; In response to the trigger signal, a first control signal is sent to the wastegate actuator to open the wastegate; and A second control signal is sent to the turbine shaft actuator to rotate the turbine of the turbocharger, wherein the rotation of the turbine causes recirculated air to flow in a recirculation flow path, the recirculation flow path including an exhaust manifold, the turbine, an exhaust wall system, and the wastegate, wherein: The exhaust wall system includes the turbine housing of the turbine, an exhaust wall disposed between the turbine and the exhaust valve, and an exhaust wall disposed between the turbine and the catalyst block; At least a portion of the recirculation flow path is adjacent to one side of the catalyst brick; as well as Heat is transferred from the recirculated air to the exhaust wall system and via one side of the catalyst brick to the catalyst brick.

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