System and method for mitigating cold start emissions by managing turbocharger turbine speed

Abstract

Systems and methods are provided for mitigating cold start emissions by managing turbocharger turbine speed. In response to an ignition on signal, a control signal is issued to a turbine shaft actuator to rotate the turbine at a first turbine speed. The first turbine speed is different from the default turbine speed. Rotation of the turbine at a default turbine speed causes the exhaust gas to have a first exhaust gas temperature after the exhaust gas passes through the turbine to a catalyst brick of the vehicle. Rotation of the turbine at the first turbine speed causes the exhaust gas to have a second exhaust gas temperature after the exhaust gas passes through the turbine to the catalyst brick. The second exhaust temperature is higher than the first exhaust temperature. When the catalyst temperature is greater than the catalyst light-off temperature, a control signal is issued to the turbine shaft actuator to rotate the turbine at a default speed.

Description

Technical Field

[0001] The technical field generally relates to vehicles, and more specifically to systems and methods for mitigating cold-start emissions by managing turbocharger turbine speed. Background Technology

[0002] Vehicles, including those 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 treat the exhaust gases before releasing them as emissions from the vehicle. Catalytic blocks usually need to reach an operating temperature, such as 500°C, to effectively treat the exhaust gases. This operating temperature is known as the catalyst ignition temperature. 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 their ignition temperature.

[0003] Therefore, it is desirable to provide systems and methods for mitigating cold-start emissions by managing turbocharger turbine speed. Other desirable features and characteristics will become apparent from the accompanying drawings and the foregoing technical and background information, as well as from the following detailed description and appended claims. Summary of the Invention

[0004] A method for mitigating cold start emissions generated by a vehicle includes: receiving an ignition on signal from an ignition switch of the vehicle at a controller; in response to the ignition on signal, issuing a first control signal from the controller to a turbine shaft actuator to rotate a turbine of a turbocharger of the vehicle at a first turbine speed, wherein the first turbine speed is different from a default turbine speed associated with the ignition on signal, wherein: rotating the turbine at the default turbine speed results in exhaust gas having a first exhaust gas temperature after exhaust gas passes through the turbine and reaches the catalyst block of the vehicle, and rotating the turbine at the first turbine speed results in exhaust gas having a second exhaust gas temperature after exhaust gas passes through the turbine and reaches the catalyst block, and the second exhaust gas temperature is higher than the first exhaust gas temperature; receiving oxygen sensor data associated with the catalyst block from an oxygen sensor at the controller; determining a catalyst temperature based on the oxygen sensor data; determining by the controller whether the catalyst temperature is greater than the catalyst ignition temperature; and based on the determination, issuing a second control signal from the controller to the turbine shaft actuator to rotate the turbine at the default speed.

[0005] In at least one embodiment, the method further includes a controller sending a first control signal to a turbine shaft actuator to cause the turbine to rotate at a first turbine speed, wherein the first turbine speed is zero, and the turbine shaft actuator responding to the first control signal to suppress the rotation of the turbine.

[0006] In at least one embodiment, the method further includes receiving a first turbine speed from a turbine model at a controller, wherein the turbine model is configured to: determine a first turbine outlet vortex of exhaust gas generated by exhaust gas flowing through the turbine while keeping the turbine at zero turbine speed, and generate a first turbine speed based on the first turbine outlet vortex, wherein a second turbine outlet vortex of exhaust gas generated by exhaust gas flowing through the turbine while rotating the turbine at the first turbine speed is smaller than the first turbine outlet vortex.

[0007] In at least one embodiment, the method further includes a controller sending a first control signal to a turbine shaft actuator to cause the turbine to rotate at a first turbine speed, wherein the first turbine speed reduces at least a portion of the first turbine outlet vortex to generate a second turbine outlet vortex.

[0008] In at least one embodiment, the method further includes receiving a first turbine speed from a turbine model at a controller, wherein the turbine model is configured to: determine a first exhaust gas expansion generated by exhaust gas flowing through the turbine while the turbine is rotating at a default turbine speed, and generate a first turbine speed less than the default turbine speed, wherein a second exhaust gas expansion generated by exhaust gas flowing through the turbine while the turbine is rotating at the first turbine speed is less than the first exhaust gas expansion.

[0009] In at least one embodiment, the first exhaust gas expansion and the second exhaust gas expansion are based in part on the exhaust flow rate from the engine's exhaust manifold to the turbine.

[0010] In at least one embodiment, the method further includes receiving a first turbine speed from a turbine model at a controller, wherein the turbine model is configured to: determine a first turbine outlet vortex of exhaust gas generated by exhaust gas flowing through the turbine while keeping the turbine at zero turbine speed; determine a first exhaust gas expansion generated by exhaust gas flowing through the turbine while rotating the turbine at a default turbine speed; and generate a first turbine speed based on the first turbine outlet vortex and less than the default turbine speed, wherein: a second turbine outlet vortex of exhaust gas generated by exhaust gas flowing through the turbine while rotating the turbine at the first turbine speed is less than the first turbine outlet vortex; and a second exhaust gas expansion generated by exhaust gas flowing through the turbine while rotating the turbine at the first turbine speed is less than the first exhaust gas expansion.

[0011] In at least one embodiment, the method further includes receiving a first turbine speed from a turbine model at a controller, wherein the turbine model is configured to generate the first turbine speed based on at least one of exhaust gas velocity, exhaust gas temperature, turbine fan blade configuration, and vehicle altitude.

[0012] In at least one embodiment, the method further includes a third control signal sent by the controller to the exhaust valve actuator to open the exhaust valve, so that a portion of the exhaust gas can bypass the turbine and flow from the vehicle's exhaust manifold to the catalyst block via the exhaust valve.

[0013] In at least one embodiment, the method further includes the controller sending a first control signal and a second control signal to the turbine shaft actuator via an electric generator unit (MGU).

[0014] A system for mitigating cold-start emissions generated by a vehicle 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 that, when executed by the at least one processor, cause the at least one processor to: receive an ignition on signal from an ignition switch of the vehicle; and, in response to the ignition on signal, issue a first control signal to a turbine shaft actuator to rotate a turbine of the vehicle's turbocharger at a first turbine speed, wherein the first turbine speed differs from a default turbine speed associated with the ignition on signal, wherein: rotating the turbine at the default turbine speed results in exhaust gas having a first exhaust gas temperature after passing through the turbine to reach the catalyst block of the vehicle, and rotating the turbine at the first turbine speed results in exhaust gas having a second exhaust gas temperature after passing through the turbine to reach the catalyst block, and the second exhaust gas temperature is higher than the first exhaust gas temperature; receive oxygen sensor data associated with the catalyst block from an oxygen sensor; determine a catalyst temperature based on the oxygen sensor data; determine whether the catalyst temperature is greater than the catalyst ignition temperature; and, based on the determination, issue a second control signal to the turbine shaft actuator to rotate the turbine at the default speed.

[0015] In at least one embodiment, at least one memory further includes instructions that, when executed by at least one processor, cause at least one processor to issue a first control signal to a turbine shaft actuator to cause the turbine to rotate at a first turbine speed, wherein the first turbine speed is zero, and the turbine shaft actuator suppresses the rotation of the turbine in response to the first control signal.

[0016] In at least one embodiment, at least one memory further includes instructions that, when executed by at least one processor, cause at least one processor to receive a first turbine speed from a turbine model, wherein the turbine model is configured to: determine a first turbine outlet vortex of exhaust gas generated by exhaust gas flowing through the turbine while keeping the turbine at zero turbine speed, and generate a first turbine speed based on the first turbine outlet vortex, wherein a second turbine outlet vortex of exhaust gas generated by exhaust gas flowing through the turbine while rotating the turbine at the first turbine speed is smaller than the first turbine outlet vortex.

[0017] In at least one embodiment, at least one memory further includes instructions that, when executed by at least one processor, cause at least one processor to issue a first control signal to the turbine shaft actuator to cause the turbine to rotate at a first turbine speed, wherein the first turbine speed reduces at least a portion of the first turbine outlet vortex to generate a second turbine outlet vortex.

[0018] In at least one embodiment, at least one memory further includes instructions that, when executed by at least one processor, cause at least one processor to receive a first turbine speed from a turbine model, wherein the turbine model is configured to: determine a first exhaust gas expansion generated by exhaust gas flowing through the turbine while the turbine is rotating at a default turbine speed, and generate a first turbine speed less than the default turbine speed, wherein a second exhaust gas expansion generated by exhaust gas flowing through the turbine while the turbine is rotating at the first turbine speed is less than the first exhaust gas expansion.

[0019] In at least one embodiment, the first exhaust gas expansion and the second exhaust gas expansion are based in part on the exhaust flow rate from the engine's exhaust manifold to the turbine.

[0020] In at least one embodiment, at least one memory further includes instructions that, when executed by at least one processor, cause at least one processor to receive a first turbine speed from a turbine model, wherein the turbine model is configured to: determine a first turbine outlet vortex of exhaust gas generated by exhaust gas flowing through the turbine while keeping the turbine at zero turbine speed; determine a first exhaust gas expansion generated by exhaust gas flowing through the turbine while rotating the turbine at a default turbine speed; and generate a first turbine speed based on the first turbine outlet vortex and less than the default turbine speed, wherein: a second turbine outlet vortex of exhaust gas generated by exhaust gas flowing through the turbine while rotating the turbine at the first turbine speed is less than the first turbine outlet vortex; and a second exhaust gas expansion generated by exhaust gas flowing through the turbine while rotating the turbine at the first turbine speed is less than the first exhaust gas expansion.

[0021] In at least one embodiment, at least one memory further includes instructions that, when executed by at least one processor, cause at least one processor to send a third control signal to the exhaust valve actuator to open the exhaust valve, so that a portion of the exhaust gas can bypass the turbine and flow from the vehicle's exhaust manifold to the catalyst block via the exhaust valve.

[0022] In at least one embodiment, at least one memory further includes instructions that, when executed by at least one processor, cause at least one processor to issue a first control signal and a second control signal to the turbine shaft actuator via an electric generator unit (MGU).

[0023] A vehicle includes a system for mitigating cold-start emissions generated by the vehicle, the system including at least one processor and at least one memory communicatively coupled to the at least one processor. The at least one memory includes instructions that, when executed by the at least one processor, cause the at least one processor to: receive an ignition on signal from an ignition switch of the vehicle; in response to the ignition on signal, issue a first control signal to a turbine shaft actuator to rotate a turbine of a turbocharger of the vehicle at a first turbine speed, wherein the first turbine speed is different from a default turbine speed associated with the ignition on signal, wherein: rotating the turbine at the default turbine speed results in exhaust gas having a first exhaust gas temperature after passing through the turbine to reach the catalyst block of the vehicle, and rotating the turbine at the first turbine speed results in exhaust gas having a second exhaust gas temperature after passing through the turbine to reach the catalyst block, and the second exhaust gas temperature is higher than the first exhaust gas temperature; receive oxygen sensor data associated with the catalyst block from an oxygen sensor; determine a catalyst temperature based on the oxygen sensor data; determine whether the catalyst temperature is greater than the catalyst ignition temperature; and based on the determination, issue a second control signal to the turbine shaft actuator to rotate the turbine at the default speed. 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;

[0028] Figure 4 This is a flowchart representation of an exemplary method for mitigating cold-start emissions according to at least one embodiment of a method for achieving zero turbine speed via a turbine;

[0029] Figure 5 This is a flowchart representation of an exemplary method for mitigating cold-start emissions by achieving turbine speed based on turbine outlet vortex, according to at least one embodiment; and

[0030] Figure 6 This is a flowchart representation of an exemplary method for managing cold-start emissions by achieving turbine speed based on exhaust gas expansion, 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 set forth in the foregoing technical field, background art, summary of the invention, or the detailed description below. As used herein, the term module refers to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (sharing a separate, dedicated, or grouped set of) and memory executing one or more software or firmware programs, combinational logic circuitry, and / or other suitable components that provide the described functionality.

[0032] Embodiments of this disclosure are described herein according to 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 this disclosure may 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 this disclosure can be practiced in combination with any number of systems, and the systems described herein are merely exemplary embodiments of this 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 represent 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 1 This 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. Although the vehicle 10 is depicted as a passenger car in the illustrated embodiment, it can be other types of vehicles, including trucks, SUVs, and RVs.

[0035] In various embodiments, the body 14 is mounted 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. Wheels 16 and 18 are rotatably coupled to the chassis 12 near corresponding angles 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 performing various driving tasks under the supervision of the driver. Level 3 automation means that the vehicle can take over all driving functions under certain conditions. All major functions are automated, including braking, steering, and acceleration. At this level, the driver can completely disengage until the vehicle informs the driver of other situations. Level 4 system means "high automation," which refers 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 means "full automation," which refers to the full-time performance of the automated driving system for all aspects of dynamic driving tasks under all road and environmental conditions that can be managed by a human driver.

[0037] As shown, 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 vehicle 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 vehicle wheels 16, 18. In various embodiments, the braking system 26 may include friction brakes, brake-by-wire brakes, a regenerative braking system such as an electric motor, and / or other suitable braking systems.

[0038] Steering system 24 is configured to influence the position of vehicle wheels 16. While 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 a shaft 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 front wheel 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 camera, ultrasonic sensor, steering wheel sensor, and / or other sensors.

[0040] Vehicle dynamics sensors provide vehicle dynamics data, including longitudinal velocity, yaw rate, lateral acceleration, longitudinal acceleration, etc. Vehicle dynamics sensors may include wheel sensors that measure information related to one or more wheels of vehicle 10. In one embodiment, the wheel sensors include wheel velocity sensors coupled to each of the wheels 16, 18 of vehicle 10. Furthermore, vehicle dynamics sensors may include one or more accelerometers (provided as part of an inertial measurement unit (IMU)) that measure information related to the acceleration of vehicle 10. In various embodiments, the accelerometers measure one or more acceleration values ​​of vehicle 10, including lateral and longitudinal acceleration and yaw rate. In at least one embodiment, vehicle dynamics sensors provide vehicle motion 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 vehicle wheels 16, 18, propulsion system 20, transmission system 22, steering system 24, and braking system 26. In various embodiments, vehicle features may further 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 48, 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 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 transmitted to vehicle 10 (wirelessly and / or via wired means) 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 can 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 typically used for executing instructions. For example, the computer-readable storage device or medium 46 can include volatile and non-volatile storage in 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 the processor 44 is powered off. The computer-readable storage device or medium 46 can be implemented using any of a number 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. 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 including 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 to automatically control components of vehicle 10 based on logic, calculations, methods, and / or algorithms. Although Figure 1Only 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, controller 34 is configured to implement ADS.

[0046] refer to Figure 2 A 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, and the at least one processor 44 is configured to execute the instructions. 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 speeds. In at least one embodiment, the cold start emission mitigation system 100 includes a turbo speed manager 200. In at least one embodiment, the cold start emission mitigation system 100 includes a turbo speed manager 200 and a turbine model 202. The controller 34 is configured to be communicatively coupled to an ignition switch 204, a turbine shaft actuator 206, one or more oxygen sensors 208, and a wastegate actuator 210. The controller 34 may include additional components to facilitate the operation of the cold start emission mitigation system 100. The operation of the cold start emission reduction system 100 will be described in more detail below.

[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, and a catalyst block 308. The turbocharger 302 includes a compressor 310, a turbine 312, a turbine shaft 314, and a turbine shaft actuator 206. The wastegate 306 includes a wastegate actuator 210. The catalyst block 308 is associated with an oxygen sensor 208. The catalyst ignition temperature is determined based on oxygen sensor data received from the oxygen sensor 208. The conversion of exhaust hydrocarbons and nitrogen oxides is determined via oxygen content.

[0048] The internal combustion engine system 300 may include additional components that facilitate the operation of the internal combustion engine system 300.

[0049] Compressor 310 draws in ambient air 316 and generates compressed air 318. Engine 304 receives compressed air 318. Fuel 320 is injected into engine 304. Compressed air 318 and fuel 320 combine to form an air-fuel mixture used by engine 304 during combustion. Exhaust gas 322 is generated by engine 304 as a byproduct of the combustion process. Cold start emission mitigation system 100 commands exhaust valve actuator 210 to place exhaust valve 306 in the fully open position.

[0050] A first portion 324 of the exhaust gas generated by engine 304 passes through turbine 312 and reaches catalyst brick 308. A second portion 326 of the exhaust gas generated by engine 304 bypasses turbine 312 and passes through exhaust valve 306 to reach catalyst brick 308. The first portion 324 and the second portion 326 of the exhaust gas are treated by catalyst brick 308 before being released into the external environment as emissions 328 via, for example, the tailgate of vehicle 10.

[0051] Vehicle 10 relies on catalyst brick 308 to treat the first and second portions 324, 326 of exhaust gas before releasing the treated exhaust gas as emission 328 from vehicle 10. Catalyst brick 308 typically needs to reach an operating temperature, such as 500°C, to effectively treat exhaust gas 324, 326. The operating temperature of catalyst brick 308 is referred to as catalyst ignition temperature. In at least one embodiment, the catalyst ignition temperature is a value somewhere in the middle of the catalyst ignition temperature range. A cold start of the internal combustion engine system 300 occurs when vehicle 10 is started after engine 304 has been off for several hours. During a cold start, vehicle 10 may emit excessive emissions 328 until catalyst brick 308 reaches catalyst ignition temperature.

[0052] The cold start emission mitigation system 100 is configured to manage the rotational speed of the turbine 312 via the turbine shaft actuator 206 to accelerate the process of the catalyst brick 308 reaching the catalyst ignition temperature, thereby mitigating cold start emissions 328. The cold start emission mitigation system 100 manages the rotation of the turbine 312 to reduce the heat transferred from the first portion 324 of the exhaust gas to the exhaust system walls before the exhaust gas 324 reaches the catalyst brick 308, thereby conserving as much heat as possible to heat the catalyst brick 308.

[0053] refer to Figure 4 A flowchart representation of an exemplary method 400 for mitigating cold-start emissions via a zero turbine speed implementation of turbine 312, according to at least one embodiment, is shown. Method 400 will be described with reference to an exemplary implementation of an embodiment of cold-start emission mitigation system 100. It will be understood from this disclosure that the sequence of operations within method 400 is not limited to, for example... Figure 4The order of execution shown may be used, but may be performed in one or more different orders as applicable and in accordance with this disclosure.

[0054] At 402, the cold start emission mitigation system 100 receives an ignition on signal from the ignition switch 204 of the vehicle 10. In at least one embodiment, the turbo speed manager 200 receives the ignition on signal from the ignition switch 204 of the vehicle 10. An ignition on signal is generated in response to activation of the ignition switch 204 to start the engine 304. The ignition switch 204 is defined as a switch for starting both non-diesel and diesel engines.

[0055] Exhaust valve 306 is a valve that controls the portion 324 of exhaust gas flowing to turbine 312 and the portion 326 of exhaust gas flowing around turbine 312 and directly to catalyst block 308. At 404, cold start emission mitigation system 100 commands exhaust valve actuator 210 to open exhaust valve 306. In at least one embodiment, cold start emission mitigation system 100 commands exhaust valve actuator 210 to partially open exhaust valve 306. In at least one embodiment, cold start emission mitigation system 100 commands exhaust valve actuator 210 to fully open exhaust valve 306. In at least one embodiment, turbine speed manager 200 commands exhaust valve actuator 210 to open exhaust valve 306. In at least one embodiment, turbine speed manager 200 commands exhaust valve actuator 210 to partially open exhaust valve 306. In at least one embodiment, the turbine speed manager 200 commands the exhaust valve actuator 210 to fully open the exhaust valve 306.

[0056] When engine 304 releases exhaust gas 322 after combustion, exhaust gas 322 has engine exhaust temperature. A portion 324 of the exhaust gas flowing through turbine 312 experiences heat loss and has turbine exhaust temperature. The turbine exhaust temperature of exhaust gas 324 after it has flowed through turbine 312 is lower than the engine exhaust temperature of exhaust gas 322 released by engine 304.

[0057] The portion 326 of exhaust gas that bypasses turbine 312 and flows through exhaust valve 306 has a temperature close to the engine exhaust temperature of exhaust gas 322 released by engine 304. Opening exhaust valve 306 allows the flow of exhaust gas 326 at engine exhaust temperature to flow through exhaust valve 306 and directly to catalyst block 308 to heat catalyst block 308.

[0058] Because the exhaust gas 326 flowing through the exhaust valve 306 experiences less heat loss than the exhaust gas 324 flowing through the turbine 312, the higher temperature of the exhaust gas 326 flowing from the exhaust valve 306 to the catalyst brick 308 allows the catalyst brick 308 to reach the catalyst ignition temperature in a shorter time than if all the exhaust gas 322 generated by the engine 304 were routed to the catalyst brick 308 through the turbine 312.

[0059] At 406, the cold start emission mitigation system 100 commands the turbine shaft actuator 206 to achieve zero turbine speed for the turbine 312. In at least one embodiment, the turbine speed manager 200 commands the turbine shaft actuator 206 to achieve zero turbine speed for the turbine 312. In at least one embodiment, the turbine shaft actuator 206 is a mechanical braking system that clamps and holds the turbine shaft 314 in place to suppress rotation of the turbine 312 in response to a command. In at least one embodiment, the turbine shaft actuator 206 is an electric generator unit (MGU). In response to a command, the MGU generates a clamping force to suppress rotation of the turbine 312.

[0060] The portion 324 of exhaust gas passing through turbine 312 experiences a temperature drop as it passes through the turbine 312. When the portion 324 of exhaust gas enters turbine 312, it has the engine exhaust temperature, and when it leaves turbine 312, it has the turbine exhaust temperature. The turbine exhaust temperature is lower than the engine exhaust temperature.

[0061] If the turbine 312 is allowed to rotate at a default turbine speed when the exhaust gas portion 324 passes through the turbine 312, then when the exhaust gas portion 324 leaves the turbine 312, the exhaust gas portion 324 will have a default turbine exhaust temperature. The default turbine exhaust temperature is lower than the engine exhaust temperature.

[0062] When the turbine shaft actuator 206 clamps and holds the turbine shaft 314 in place to suppress the rotation of the turbine 312, the exhaust gas portion 324 can have an elevated turbine exhaust temperature as it exits the turbine 312. This elevated turbine exhaust temperature can be lower than the engine exhaust temperature but higher than the default turbine exhaust temperature. When the rotation of the turbine 312 is suppressed, the turbine exit vortex associated with the exhaust gas portion 324 exiting the turbine 312 will be lower. Lower vortex means less heat is absorbed into the exhaust walls.

[0063] When the portion 324 of exhaust gas with an elevated turbine exhaust temperature flows from the turbine 312 to the catalyst brick 308, the elevated turbine exhaust temperature heats the catalyst brick 308 at a faster rate than the default turbine exhaust temperature associated with the turbine 312 rotating at the default turbine speed. The flow of the portion 324 of exhaust gas with an elevated turbine exhaust temperature to the catalyst brick 308 allows the catalyst brick 308 to reach its ignition temperature in a shorter time than the first portion 324 of exhaust gas with a default turbine exhaust temperature.

[0064] At 408, the cold start emission mitigation system 100 determines the catalyst temperature of the catalyst brick 308 based on oxygen sensor data received from the oxygen sensor 208 associated with the catalyst brick 308. In at least one embodiment, the turbine speed manager 200 determines the catalyst temperature of the catalyst brick 308 based on oxygen sensor data received from the oxygen sensor 208 associated with the catalyst brick 308. The catalyst temperature sensor 208 provides the catalyst temperature of the catalyst brick 308.

[0065] At 410, the cold start emission mitigation system 100 determines whether the catalyst temperature is greater than the catalyst ignition temperature. In at least one embodiment, the turbine speed manager 200 determines whether the catalyst temperature is greater than the catalyst ignition temperature. If it is determined that the catalyst temperature is not greater than the catalyst ignition temperature, 410 is repeated. If it is determined that the catalyst temperature is greater than the catalyst ignition temperature, at 412, the cold start emission mitigation system 100 commands the turbine shaft actuator 206 to release the clamping of the turbine shaft 314 and allow the turbine 312 to rotate at the default turbine speed. In at least one embodiment, if it is determined that the catalyst temperature is greater than the catalyst ignition temperature, at 412, the turbine speed manager 200 commands the turbine shaft actuator 206 to release the clamping of the turbine shaft 314 and allow the turbine 312 to rotate at the default turbine speed.

[0066] refer to Figure 5 A flowchart representation of an exemplary method 500 for mitigating cold-start emissions by achieving turbine speed based on turbine outlet vortex, according to at least one embodiment, is shown. Method 500 will be described with reference to an exemplary implementation of an embodiment of cold-start emission mitigation system 100. It will be understood from this disclosure that the sequence of operations within method 500 is not limited to, for example… Figure 5 The order of execution shown may be used, but may be performed in one or more different orders as applicable and in accordance with this disclosure.

[0067] At 502, the cold start emission mitigation system 100 receives an ignition on signal from the ignition switch 204 of the vehicle 10. In at least one embodiment, the turbo speed manager 200 receives the ignition on signal from the ignition switch 204 of the vehicle 10. An ignition on signal is generated in response to activation of the ignition switch 204 to start the engine 304. The ignition switch 204 is defined as a switch for starting both non-diesel and diesel engines.

[0068] Exhaust valve 306 is a valve that controls the portion 324 of exhaust gas flowing to turbine 312 and the portion 326 of exhaust gas flowing around turbine 312 and directly to catalyst block 308. At 504, cold start emission mitigation system 100 commands exhaust valve actuator 210 to open exhaust valve 306. In at least one embodiment, cold start emission mitigation system 100 commands exhaust valve actuator 210 to partially open exhaust valve 306. In at least one embodiment, cold start emission mitigation system 100 commands exhaust valve actuator 210 to fully open exhaust valve 306. In at least one embodiment, turbine speed manager 200 commands exhaust valve actuator 210 to open exhaust valve 306. In at least one embodiment, turbine speed manager 200 commands exhaust valve actuator 210 to partially open exhaust valve 306. In at least one embodiment, the turbine speed manager 200 commands the exhaust valve actuator 210 to fully open the exhaust valve 306.

[0069] When engine 304 releases exhaust gas 322 after combustion, exhaust gas 322 has engine exhaust temperature. A portion 324 of the exhaust gas flowing through turbine 312 experiences heat loss and has turbine exhaust temperature. The turbine exhaust temperature of exhaust gas 324 after it has flowed through turbine 312 is lower than the engine exhaust temperature of exhaust gas 322 released by engine 304.

[0070] The portion 326 of exhaust gas that bypasses turbine 312 and flows through exhaust valve 306 has a temperature close to the engine exhaust temperature of exhaust gas 322 released by engine 304. Opening exhaust valve 306 allows the flow of exhaust gas 326 at engine exhaust temperature to flow through exhaust valve 306 and directly to catalyst block 308 to heat catalyst block 308.

[0071] Because the exhaust gas 326 flowing through the exhaust valve 306 experiences less heat loss than the exhaust gas 324 flowing through the turbine 312, the higher temperature of the exhaust gas 326 flowing from the exhaust valve 306 to the catalyst brick 308 allows the catalyst brick 308 to reach the catalyst ignition temperature in a shorter time than if all the exhaust gas 322 generated by the engine 304 were routed to the catalyst brick 308 through the turbine 312.

[0072] At 506, turbine speed manager 200 commands turbine shaft actuator 206 to achieve an adjusted turbine speed for turbine 312. Turbine speed manager 200 receives the adjusted turbine speed from turbine model 202. Turbine model 202 determines the adjusted turbine speed of turbine 312 based on turbine exit vortex. Exhaust gas portion 324 flows through turbine 312 and exits turbine 312 at turbine outlet. As exhaust gas portion 324 exits turbine outlet, it exhibits turbine exit vortex. Turbine exit vortex is turbulence generated by exhaust gas portion 324 flowing through turbine 312. As exhaust gas portion 324 flows from turbine outlet to catalyst brick 308, turbine exit vortex causes a temperature drop in exhaust gas portion 324.

[0073] When turbine 312 rotates at the default turbine speed, the turbine exit vortex has a default turbine exit vortex generated by the portion 324 of the exhaust gas flowing through turbine 312. When the portion 324 of the exhaust gas reaches catalyst brick 308, the portion 324 of the exhaust gas will have a default turbine exhaust temperature. The default turbine exhaust temperature is based on the default turbine output vortex.

[0074] Turbine model 202 is configured to determine a zero-turbine-speed turbine outlet vortex associated with maintaining turbine 312 at zero turbine speed as exhaust gas 324 flows through turbine 312. If a portion of exhaust gas 324 flows through turbine 312 while turbine 312 is maintained at zero turbine speed, then when the portion of exhaust gas 324 reaches catalyst brick 308, exhaust gas 324 will have a zero-turbine-outlet-speed exhaust temperature.

[0075] Turbine model 202 is configured to determine an adjusted turbine speed for generating a reduced turbine exit vortex in turbine 312. The reduced turbine exit vortex is less than the zero turbine speed turbine exit vortex and the default turbine exit vortex. The adjusted turbine speed is designed to counteract the zero turbine speed turbine exit vortex, resulting in the lowest possible reduced turbine exit vortex generated at the adjusted turbine speed. When a portion of exhaust gas 324 flows through turbine 312 at the adjusted turbine speed, the reduced turbine exit vortex will cause the exhaust gas 324 to have an increased turbine exhaust temperature when it reaches catalyst brick 308. The reduced turbine exit vortex will decrease heat transfer to the internal exhaust walls. The increased turbine exhaust temperature is greater than the default turbine exhaust temperature and the zero turbine exit speed exhaust temperature. When the portion of exhaust gas 324 with the increased turbine exhaust temperature reaches catalyst brick 308, the increased turbine exhaust temperature heats catalyst brick 308 at a faster rate than if the exhaust gas portion 324 had the default turbine exhaust temperature.

[0076] In at least one embodiment, the turbine model 202 is trained using engine test data associated with the internal combustion engine system 300 prior to installation in the vehicle 10. In at least one embodiment, the turbine model 202 is a mathematical model configured to calculate an adjusted turbine speed. In at least one embodiment, the turbine model 202 is configured to generate the adjusted turbine speed based in part on one or more of the following: exhaust gas flow rate of a portion 324 of the exhaust gas, exhaust gas temperature, turbine fan blade configuration of the turbine 312, and altitude of the vehicle 10.

[0077] At 508, the cold start emission mitigation system determines the catalyst temperature of catalyst brick 308 based on oxygen sensor data received from oxygen sensor 208 associated with catalyst brick 308. In at least one embodiment, turbine speed manager 200 determines the catalyst temperature of catalyst brick 308 based on oxygen sensor data received from oxygen sensor 208 associated with catalyst brick 308.

[0078] At 510, the cold start emission mitigation system 100 determines whether the catalyst temperature is greater than the catalyst ignition temperature. In at least one embodiment, the turbine speed manager 200 determines whether the catalyst temperature is greater than the catalyst ignition temperature. If it is determined that the catalyst temperature is not greater than the catalyst ignition temperature, 510 is repeated. If it is determined that the catalyst temperature is greater than the catalyst ignition temperature, at 512, the cold start emission mitigation system 100 commands the turbine shaft actuator 206 to rotate the turbine 312 at a default turbine speed. In at least one embodiment, if it is determined that the catalyst temperature is greater than the catalyst ignition temperature, at 512, the turbine speed manager 200 commands the turbine shaft actuator 206 to rotate the turbine 312 at a default turbine speed.

[0079] refer to Figure 6 A flowchart representation of an exemplary method 600 for managing cold start emissions by achieving turbine speed based on exhaust gas expansion, according to at least one embodiment, is shown. Method 600 will be described with reference to an exemplary implementation of an embodiment of a cold start emission mitigation system 100. It will be understood from this disclosure that the sequence of operations within method 600 is not limited to, for example… Figure 6 The order of execution shown may be used, but may be performed in one or more different orders as applicable and in accordance with this disclosure.

[0080] At 602, the cold start emission mitigation system 100 receives an ignition on signal from the ignition switch 204 of the vehicle 10. In at least one embodiment, the turbo speed manager 200 receives the ignition on signal from the ignition switch 204 of the vehicle 10. An ignition on signal is generated in response to activation of the ignition switch 204 to start the engine 304. The ignition switch 204 is defined as a switch for starting both non-diesel and diesel engines.

[0081] Exhaust valve 306 is a valve that controls the portion 324 of exhaust gas flowing to turbine 312 and the portion 326 of exhaust gas flowing around turbine 312 and directly to catalyst block 308. At 604, cold start emission mitigation system 100 commands exhaust valve actuator 210 to open exhaust valve 306. In at least one embodiment, cold start emission mitigation system 100 commands exhaust valve actuator 210 to partially open exhaust valve 306. In at least one embodiment, cold start emission mitigation system 100 commands exhaust valve actuator 210 to fully open exhaust valve 306. In at least one embodiment, turbine speed manager 200 commands exhaust valve actuator 210 to open exhaust valve 306. In at least one embodiment, turbine speed manager 200 commands exhaust valve actuator 210 to partially open exhaust valve 306. In at least one embodiment, the turbine speed manager 200 commands the exhaust valve actuator 210 to fully open the exhaust valve 306.

[0082] When engine 304 releases exhaust gas 322 after combustion, exhaust gas 322 has engine exhaust temperature. A portion 324 of the exhaust gas flowing through turbine 312 experiences heat loss and has turbine exhaust temperature. The turbine exhaust temperature of exhaust gas 324 after it has flowed through turbine 312 is lower than the engine exhaust temperature of exhaust gas 322 released by engine 304.

[0083] The portion 326 of exhaust gas that bypasses turbine 312 and flows through exhaust valve 306 has a temperature close to the engine exhaust temperature of exhaust gas 322 released by engine 304. Opening exhaust valve 306 allows the flow of exhaust gas 326 at engine exhaust temperature to flow through exhaust valve 306 and directly to catalyst block 308 to heat catalyst block 308.

[0084] Because the exhaust gas 326 flowing through the exhaust valve 306 experiences less heat loss than the exhaust gas 324 flowing through the turbine 312, the higher temperature of the exhaust gas 326 flowing from the exhaust valve 306 to the catalyst brick 308 allows the catalyst brick 308 to reach the catalyst ignition temperature in a shorter time than if all the exhaust gas 322 generated by the engine 304 were routed to the catalyst brick 308 through the turbine 312.

[0085] At 606, the turbine speed manager 200 commands the turbine shaft actuator 206 to achieve an adjusted turbine speed for the turbine 312. The turbine speed manager 200 receives the adjusted turbine speed from the turbine model 202. The turbine model 202 determines the adjusted turbine speed of the turbine 312 based on exhaust gas expansion. A portion 324 of the exhaust gas flows through the turbine 312 and exits at the turbine outlet. As the exhaust gas portion 324 exits the turbine outlet, it undergoes exhaust gas expansion. This expansion is generated by the exhaust gas portion 324 flowing through the turbine 312. As the exhaust gas portion 324 flows from the turbine outlet towards the catalyst brick 308, the expansion causes a temperature drop within the exhaust gas portion 324.

[0086] When turbine 312 rotates at the default turbine speed, the exhaust gas expansion has a default exhaust gas expansion generated by the portion 324 of the exhaust gas flowing through turbine 312. When the exhaust gas portion 324 reaches catalyst brick 308, the exhaust gas portion 324 will have a default turbine exhaust temperature. The default turbine exhaust temperature is based on the default exhaust gas expansion.

[0087] Turbine model 202 is configured to determine an adjusted turbine speed for generating reduced exhaust gas expansion in turbine 312. The reduced exhaust gas expansion is less than the default exhaust gas expansion. The adjusted turbine speed is less than the default turbine speed and is designed to minimize exhaust gas expansion. When a portion of exhaust gas 324 flows through turbine 312 and turbine 312 rotates at the adjusted turbine speed, the reduced exhaust gas expansion will cause the exhaust gas 324 to have an increased turbine exhaust temperature when it reaches catalyst brick 308. The increased turbine exhaust temperature is greater than the default turbine exhaust temperature. When the portion of exhaust gas 324 with the increased turbine exhaust temperature reaches catalyst brick 308, the increased turbine exhaust temperature heats catalyst brick 308 at a faster rate than if the exhaust gas portion 324 had the default turbine exhaust temperature.

[0088] In at least one embodiment, the turbine model 202 is trained using engine test data associated with the internal combustion engine system 300 prior to installation in the vehicle 10. In at least one embodiment, the turbine model 202 is a mathematical model configured to calculate an adjusted turbine speed. In at least one embodiment, the turbine model 202 is configured to generate the adjusted turbine speed based in part on one or more of the following: exhaust gas flow rate of a portion 324 of the exhaust gas, exhaust gas temperature, turbine fan blade configuration of the turbine 312, and altitude of the vehicle 10. In at least one embodiment, the default exhaust gas expansion and contraction are based in part on the exhaust gas flow rate from the exhaust manifold of the vehicle 10 to the turbine 312.

[0089] At 608, the cold start emission mitigation system determines the catalyst temperature of catalyst brick 308 based on oxygen sensor data received from oxygen sensor 208 associated with catalyst brick 308. In at least one embodiment, turbine speed manager 200 determines the catalyst temperature of catalyst brick 308 based on oxygen sensor data received from oxygen sensor 208 associated with catalyst brick 308.

[0090] At 610, the cold start emission mitigation system 100 determines whether the catalyst temperature is greater than the catalyst ignition temperature. In at least one embodiment, the turbine speed manager 200 determines whether the catalyst temperature is greater than the catalyst ignition temperature. If it is determined that the catalyst temperature is not greater than the catalyst ignition temperature, 610 is repeated. If it is determined that the catalyst temperature is greater than the catalyst ignition temperature, at 612, the cold start emission mitigation system 100 commands the turbine shaft actuator 206 to rotate the turbine 312 at a default turbine speed. In at least one embodiment, if it is determined that the catalyst temperature is greater than the catalyst ignition temperature, at 612, the turbine speed manager 200 commands the turbine shaft actuator 206 to rotate the turbine 312 at a default turbine speed.

[0091] In at least one embodiment, turbine model 202 is configured to determine a first turbine outlet vortex of exhaust gas 324 generated by exhaust gas 324 flowing through turbine 312 while maintaining turbine 312 at zero turbine speed. Turbine model 202 is configured to determine a first exhaust gas expansion generated by exhaust gas 324 flowing through turbine 312 while rotating turbine 312 at a default turbine speed. Turbine model 202 is configured to generate an adjusted turbine speed less than the default turbine speed based on the first turbine outlet vortex. A second turbine outlet vortex of exhaust gas 324 generated by exhaust gas 324 flowing through turbine 312 while rotating turbine 312 at the adjusted turbine speed is smaller than the first turbine outlet vortex. A second exhaust gas expansion generated by exhaust gas 324 flowing through turbine 312 while rotating turbine 312 at the first turbine speed is smaller than the first exhaust gas expansion.

[0092] 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 mitigating cold-start emissions generated by a vehicle, comprising: The controller receives an ignition on signal from the vehicle's ignition switch. In response to the ignition on signal, the controller sends a first control signal to the turbine shaft actuator to cause the turbine of the vehicle's turbocharger to rotate at a first turbine speed, wherein the first turbine speed is different from the default turbine speed associated with the ignition on signal, wherein: The turbine rotates at the default turbine speed, resulting in the exhaust gas having a first exhaust gas temperature after passing through the turbine and reaching the catalyst block of the vehicle. The turbine rotating at the first turbine speed results in the exhaust gas having a second exhaust gas temperature after it passes through the turbine and reaches the catalyst brick. The temperature of the second exhaust gas is higher than that of the first exhaust gas; The controller receives oxygen sensor data associated with the catalyst brick from the oxygen sensor; the catalyst temperature is determined based on the oxygen sensor data. The controller determines whether the catalyst temperature is greater than the catalyst ignition temperature; and Based on the determination, the controller sends a second control signal to the turbine shaft actuator to cause the turbine to rotate at the default speed.

2. The method of claim 1, further comprising the controller sending the first control signal to the turbine shaft actuator to cause the turbine to rotate at the first turbine speed, wherein, The first turbine speed is zero, and the turbine shaft actuator suppresses the rotation of the turbine in response to the first control signal.

3. The method of claim 1, further comprising receiving the first turbine speed from the turbine model at the controller, wherein, The turbine model is configured as follows: Determine the first turbine outlet vortex of the exhaust gas generated by the exhaust gas flowing through the turbine while maintaining the turbine at zero turbine speed, and The first turbine speed is generated based on the first turbine outlet vortex, wherein, while the turbine is rotating at the first turbine speed, the second turbine outlet vortex of the exhaust gas generated by the exhaust gas flowing through the turbine is smaller than the first turbine outlet vortex.

4. The method of claim 1, further comprising receiving the first turbine speed from the turbine model at the controller, wherein, The turbine model is configured as follows: Determine the first exhaust gas expansion generated by the exhaust gas flowing through the turbine while the turbine is rotating at the default turbine speed, and A first turbine speed is generated that is less than the default turbine speed, wherein, while the turbine is rotating at the first turbine speed, the second exhaust gas expansion generated by the exhaust gas flowing through the turbine is less than the first exhaust gas expansion.

5. The method according to claim 4, wherein, The first exhaust gas expansion and the second exhaust gas expansion are based in part on the exhaust flow rate from the engine's exhaust manifold to the turbine.

6. The method of claim 1, further comprising receiving the first turbine speed from the turbine model at the controller, wherein, The turbine model is configured as follows: A first turbine outlet vortex of exhaust gas generated by the exhaust gas flowing through the turbine is determined while the turbine is kept at zero turbine speed. Determine the first exhaust gas expansion generated by the exhaust gas flowing through the turbine while the turbine is rotating at the default turbine speed, and The first turbine speed is generated based on the first turbine outlet vortex and is less than the default turbine speed. in: While the turbine rotates at the first turbine speed, the second turbine outlet vortex of the exhaust gas generated by the exhaust gas flowing through the turbine is smaller than the first turbine outlet vortex, and While the turbine is rotating at the first turbine speed, the expansion of the second exhaust gas generated by the exhaust gas flowing through the turbine is less than the expansion of the first exhaust gas.

7. The method of claim 1, further comprising receiving the first turbine speed from the turbine model at the controller, wherein, The turbine model is configured to generate the first turbine speed based on at least one of exhaust gas velocity, exhaust gas temperature, turbine fan blade configuration, and the vehicle's altitude.

8. The method of claim 1, further comprising the controller sending a third control signal to the wastegate actuator to open the wastegate, such that a portion of the exhaust gas can bypass the turbine and flow from the vehicle's exhaust manifold to the catalyst block via the wastegate.

9. The method of claim 1, further comprising the controller sending the first control signal and the second control signal to the turbine shaft actuator via an electric generator unit (MGU).

10. A system for mitigating cold-start emissions generated by a vehicle, 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: Receive an ignition on signal from the ignition switch of the vehicle; In response to the ignition on signal, a first control signal is sent to the turbine shaft actuator to cause the turbine of the vehicle's turbocharger to rotate at a first turbine speed, wherein the first turbine speed is different from the default turbine speed associated with the ignition on signal, wherein: The turbine rotates at the default turbine speed, resulting in the exhaust gas having a first exhaust gas temperature after passing through the turbine and reaching the catalyst block of the vehicle. The turbine rotating at the first turbine speed results in the exhaust gas having a second exhaust gas temperature after it passes through the turbine and reaches the catalyst brick. The temperature of the second exhaust gas is higher than that of the first exhaust gas; Receive oxygen sensor data associated with the catalyst brick from the oxygen sensor; The catalyst temperature is determined based on the oxygen sensor data. Determine whether the catalyst temperature is greater than the catalyst ignition temperature; and Based on the determination, a second control signal is sent to the turbine shaft actuator to cause the turbine to rotate at the default speed.

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