Method and system for reducing cold start emissions generated by a vehicle

Abstract

A control signal is sent to a turboshaft actuator to rotate a turbine at an initial turbine speed in response to an ignition activation signal. This initial turbine speed differs from a standard turbine speed. Rotating the turbine at the standard turbine speed results in the exhaust gas reaching a first exhaust gas temperature after passing through the turbine and entering the vehicle's catalytic converter. Rotating the turbine at the initial turbine speed also results in the exhaust gas reaching a second exhaust gas temperature after passing through the turbine and entering the catalytic converter. This second exhaust gas temperature is higher than the first. When the catalytic converter temperature exceeds a catalytic converter activation temperature, a control signal is sent to the turboshaft actuator to rotate the turbine at the standard speed.The first control signal is sent by the controller to the turboshaft actuator to rotate the turbine at the first turbine speed. The first turbine speed is zero, and the turboshaft actuator prevents the turbine from rotating in response to the first control signal.

Description

[0001] The technical field generally concerns vehicles and specifically concerns systems and methods for reducing cold start emissions generated by a vehicle by managing the turbocharger turbine speed.

[0002] Vehicles containing internal combustion engines produce exhaust gases as a byproduct of the combustion process. Such vehicles often rely on a catalyst element within a catalytic converter to process the exhaust gases before releasing them as emissions from the vehicle. Catalyst elements typically need to reach an operating temperature, such as 500 °C, to effectively process the exhaust gases. This operating temperature is known as the catalyst start-up 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 levels of exhaust gases until the catalyst element reaches its start-up temperature.

[0003] US 2011 / 0107739A1 Warm-up system for warming an exhaust gas purification catalyst located in an exhaust duct of a turbocharged engine. The warm-up system comprises an electric motor coupled to a turbine of the turbocharger and a control device that operates the electric motor to exert a counter-torque on the turbine when the exhaust gas purification catalyst needs to be warmed up.

[0004] Accordingly, the object of the invention is to provide systems and methods for reducing cold-start emissions by managing the turbocharger turbine speed. Other desirable features and characteristics will become apparent from the following detailed description and the attached claims in conjunction with the attached drawings and the preceding technical field and background.

[0005] The object of the invention is solved by means of a method for reducing cold start emissions generated by a vehicle, which includes: receiving, at a control unit, an ignition switch signal from an ignition switch of the vehicle, outputting, by the control unit, a first control signal to a turbo shaft actuator in order to rotate a turbine of a turbocharger of the vehicle at a first turbine speed in response to the ignition switch signal.

[0006] The first turbine speed differs from a standard turbine speed, which is associated with the ignition switch-on signal.Rotation of the turbine at the standard turbine speed results in the exhaust gas having a first exhaust gas temperature after passing through the turbine to a catalytic converter block of the vehicle; rotation of the turbine at the first turbine speed results in the exhaust gas having a second exhaust gas temperature after passing through the turbine to the catalytic converter block, and the second exhaust gas temperature is higher than the first exhaust gas temperature; the controller receives oxygen sensor data assigned to the catalytic converter block from an oxygen sensor; determines a catalytic converter temperature based on the oxygen sensor data; determines, by the controller, whether the catalytic converter temperature is greater than a catalytic converter start-up temperature; and outputs, by the controller, a second control signal to the turboshaft actuator to rotate the turbine at the standard speed based on this determination.The process further includes the controller sending the first control signal to the turboshaft actuator to rotate the turbine at the first turbine speed. The first turbine speed is zero, and the turboshaft actuator prevents the turbine from rotating in response to the first control signal.

[0007] According to one embodiment, the method further comprises receiving, at the control point, the first turbine speed from a turbine model. The turbine model is configured to: determine a first turbine exhaust vortex resulting from the exhaust gas flowing through the turbine while the turbine is held at a turbine speed of zero, and generate the first turbine speed based on the first turbine exhaust vortex. A second turbine exhaust vortex resulting from the exhaust gas flowing through the turbine, while the turbine is rotating at the first turbine speed, is smaller than the first turbine exhaust vortex.

[0008] According to a further embodiment, the method also includes outputting the first control signal by the controller to the turboshaft actuator to rotate the turbine at the first turbine speed. The first turbine speed reduces at least a portion of the first turbine outlet vortex to generate the second turbine outlet vortex.

[0009] According to a further embodiment, the method further comprises receiving, at the control point, the first turbine speed from a turbine model. The turbine model is configured to: determine a first exhaust gas expansion resulting from the exhaust gas flowing through the turbine while the turbine is rotated at the standard turbine speed, and generate the first turbine speed such that it is lower than the standard turbine speed. A second exhaust gas expansion resulting from the exhaust gas flowing through the turbine, while the turbine is rotated at the first turbine speed, is smaller than the first exhaust gas expansion.

[0010] According to another embodiment, the first exhaust gas expansion and the second gas expansion are partly based on an exhaust gas flow rate from an exhaust manifold of an engine to the turbine.

[0011] According to a further embodiment, the method further comprises receiving, at the control point, the first turbine speed from a turbine model. The turbine model is configured to: determine a first turbine outlet vortex of the exhaust gas resulting from the exhaust gas flowing through the turbine while the turbine is held at a turbine speed of zero; determine a first exhaust gas expansion resulting from the exhaust gas flowing through the turbine while the turbine is rotated at the standard turbine speed; and generate the first turbine speed based on the first turbine outlet vortex and such that it is lower than the standard turbine speed.A second turbine outlet vortex of the exhaust gas, resulting from the exhaust gas flowing through the turbine, is smaller than the first turbine outlet vortex while the turbine is rotating at the first turbine speed, and a second exhaust gas expansion, resulting from the exhaust gas flowing through the turbine while the turbine is rotating at the first turbine speed, is smaller than the first exhaust gas expansion.

[0012] According to a further embodiment, the method further comprises receiving, at the control unit, the first turbine speed from a turbine model. The turbine model is configured to generate the first turbine speed based on at least one of the following: exhaust flow rate, exhaust temperature, turbine fan blade configuration, and vehicle altitude.

[0013] According to a further embodiment, the method further comprises the output of a third control signal by the controller to a wastegate actuator to open a wastegate in order to allow part of the exhaust gas to bypass the turbine and flow from an exhaust manifold of the vehicle via the wastegate to the catalyst block.

[0014] According to a further embodiment, the method further comprises outputting, by means of the control, the first control signal and the second control signal to the turboshaft actuator via a motor generator unit, MGU.

[0015] According to the invention, a system for reducing cold-start emissions generated by a vehicle is also provided, comprising at least one processor and at least one memory that is communicatively coupled to the at least one processor. The at least one memory comprises instructions which, 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; output a first control signal to a turboshaft actuator to rotate a turbine of a turbocharger of the vehicle at a first turbine speed in response to the ignition-on signal. The first turbine speed differs from a standard turbine speed associated with the ignition-on signal.Rotation of the turbine at the standard turbine speed results in the exhaust gas having a first exhaust gas temperature after passing through the turbine to a catalytic converter block of the vehicle. Rotation of the turbine at the first turbine speed results in the exhaust gas having a second exhaust gas temperature after passing through the turbine to the catalytic converter block, and the second exhaust gas temperature is higher than the first exhaust gas temperature. Oxygen sensor data assigned to the catalytic converter block is received from an oxygen sensor. A catalytic converter temperature is determined based on the oxygen sensor data. It is determined whether the catalytic converter temperature is higher than a catalytic converter start-up temperature. A second control signal is then output to the turboshaft actuator to rotate the turbine at the standard speed based on this determination.The at least one memory further comprises instructions which, when executed by the at least one processor, cause the at least one processor to output the first control signal to the turboshaft actuator in order to rotate the turbine at the first turbine speed. The first turbine speed is zero, and the turboshaft actuator prevents the turbine from rotating in response to the first control signal.

[0016] According to a further embodiment, the at least one memory further comprises instructions which, when executed by the at least one processor, cause the at least one processor to receive the first turbine speed from a turbine model. The turbine model is configured to determine a first turbine exhaust vortex resulting from the exhaust gas flowing through the turbine while the turbine is held at a turbine speed of zero, and to generate the first turbine speed based on the first turbine exhaust vortex. A second turbine exhaust vortex resulting from the exhaust gas flowing through the turbine, while the turbine is rotating at the first turbine speed, is smaller than the first turbine exhaust vortex.

[0017] According to a further embodiment, the at least one memory further comprises instructions which, when executed by the at least one processor, cause the at least one processor to output the first control signal to the turboshaft actuator in order to rotate the turbine at the first turbine speed. The first turbine speed reduces at least a portion of the first turbine outlet vortex to generate the second turbine outlet vortex.

[0018] According to a further embodiment, the at least one memory further comprises instructions which, when executed by the at least one processor, cause the at least one processor to receive the first turbine speed from a turbine model. The turbine model is configured to determine a first exhaust gas expansion resulting from the exhaust gas flowing through the turbine while the turbine is rotating at the standard turbine speed, and to generate the first turbine speed such that it is lower than the standard turbine speed. A second exhaust gas expansion resulting from the exhaust gas flowing through the turbine while the turbine is rotating at the first turbine speed is also lower than the first exhaust gas expansion.

[0019] According to another embodiment, the first exhaust gas expansion and the second gas expansion are partly based on an exhaust gas flow rate from an exhaust manifold of an engine to the turbine.

[0020] According to a further embodiment, the at least one memory further comprises instructions which, when executed by the at least one processor, cause the at least one processor to receive the first turbine speed from a turbine model. The turbine model is configured to determine a first turbine outlet vortex of the exhaust gas resulting from the exhaust gas flowing through the turbine while the turbine is held at a turbine speed of zero, to determine a first exhaust gas expansion resulting from the exhaust gas flowing through the turbine while the turbine is rotated at the standard turbine speed, and to generate the first turbine speed based on the first turbine outlet vortex and such that it is lower than the standard turbine speed.A second turbine outlet vortex of the exhaust gas, resulting from the exhaust gas flowing through the turbine, is smaller than the first turbine outlet vortex while the turbine is rotating at the first turbine speed, and a second exhaust gas expansion, resulting from the exhaust gas flowing through the turbine while the turbine is rotating at the first turbine speed, is smaller than the first exhaust gas expansion.

[0021] According to a further embodiment, the at least one memory further comprises instructions which, when executed by the at least one processor, cause the at least one processor to output a third control signal to a wastegate actuator in order to open a wastegate in order to allow part of the exhaust gas to bypass the turbine and flow from an exhaust manifold of the vehicle via the wastegate to the catalyst block.

[0022] According to a further embodiment, the at least one memory further comprises instructions which, when executed by the at least one processor, cause the at least one processor to output the first control signal and the second control signal to the turboshaft actuator via a motor generator unit (MGU).

[0023] In one application case, a vehicle comprises the system according to the invention and its embodiments.

[0024] The exemplary embodiments are described below in conjunction with the following drawing figures, where the same reference numerals denote the same elements and where: Fig. 1 is a functional block diagram of a vehicle that includes a cold start emission attenuation system; Fig. 2 is a functional block diagram of a control system that includes a cold start emission attenuation system; Fig. 3 is a functional block diagram of an internal combustion engine system; Fig. 4 is a flowchart representation of an exemplary method for reducing cold start emissions by implementing a zero turbine speed of a turbine; Fig. 5 is a flowchart representation of an exemplary method for reducing cold-start emissions by implementing a turbine speed based on turbine outlet turbulence; and Fig. Figure 6 is a flowchart representation of an exemplary procedure for managing cold start emissions by implementing a turbine speed based on exhaust gas expansion.

[0025] The following detailed description is merely exemplary and is not intended to limit the filing and uses. Furthermore, there is no intention to be bound by any express or implied theory presented in the preceding technical field, background, brief description, or the detailed description that follows. As used herein, the term module refers to an application-specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or grouped), and memory executing one or more software or firmware programs, a combinational logic circuit, and / or other suitable components providing the described functionality.

[0026] Embodiments of the present disclosure can be described herein with respect to functional and / or logical block components and various processing steps. It is understood that such block components can be implemented by any number of hardware, software, and / or firmware components configured to perform the specified functions. For example, an embodiment of the present disclosure may employ various integrated circuit components, such as memory elements, digital signal processing elements, logic elements, lookup tables, or the like, which can perform a variety of functions under the control of one or more microprocessors or other control devices.Furthermore, the person skilled in the art will recognize that embodiments of the present disclosure can be practiced in connection with any number of systems and that the systems described herein are merely exemplary embodiments of the present disclosure.

[0027] For the sake of brevity, conventional techniques relating to signal processing, data transmission, signaling, control, and other functional aspects of the systems (and the individual operating components of the systems) may not be described in detail herein. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and / or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in an embodiment of the present disclosure.

[0028] With reference to Fig. Figure 1 shows a functional block diagram of a vehicle incorporating a cold start emission reduction system 100 according to at least one embodiment. The vehicle 10 generally includes a chassis 12, a body 14, front wheels 16, and rear wheels 18. While the vehicle 10 is depicted as a passenger car in the illustrated embodiment, the vehicle 10 can be other types of vehicles, including trucks, all-terrain vehicles (SUVs), and recreational vehicles (RVs).

[0029] In various embodiments, the body 14 is arranged on the chassis 12 and essentially encloses components of the vehicle 10. The body 14 and the chassis 12 can together form a frame. The wheels 16, 18 are rotatably coupled to the chassis 12 near their respective corners of the body 14.

[0030] In various embodiments, the vehicle 10 is an autonomous or semi-autonomous vehicle that is automatically controlled to transport passengers and / or cargo from one place to another. For example, in one exemplary embodiment, the vehicle 10 is a so-called Level Two, Level Three, Level Four, or Level Five automation system. Level Two automation means that the vehicle assists the driver with various driving tasks under driver supervision. Level Three automation means that, under certain circumstances, the vehicle can take over all driving functions. All major functions are automated, including braking, steering, and accelerating. At this level, the driver can completely relinquish control until the vehicle instructs the driver otherwise.A Level Four system indicates "high automation" and refers to the driving-mode-specific performance of all aspects of the dynamic driving task by an automated driving system, even if a human driver does not respond appropriately to a request for intervention. A Level Five system indicates "full automation" and refers to the full-time performance of all aspects of the dynamic driving task by an automated driving system under all road and environmental conditions that can be managed by a human driver.

[0031] As shown, the vehicle 10 generally includes a drive 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 drive system 20 is configured to generate power to propel the vehicle. The drive system 20 includes an internal combustion engine (ICE). In various embodiments, the drive system 20 may also include an electric machine, such as a traction motor, a fuel cell propulsion system, and / or any other type of drive configuration. The transmission system 22 is configured to transmit power from the drive system 20 to the vehicle wheels 16, 18 according to selectable speed ratios.According to various embodiments, the transmission system 22 can include a multi-stage automatic transmission, a continuously variable transmission, or another suitable transmission. The braking system 26 is configured to provide braking torque to the vehicle wheels 16 and 18. The braking system 26 can, in various embodiments, include friction brakes, brake-by-wire, a regenerative braking system such as an electric motor, and / or other suitable braking systems.

[0032] The steering system 24 is configured to influence the position of the vehicle wheels 16. Although shown for illustrative purposes as including a steering wheel and steering column, in some embodiments considered within the scope of this disclosure, the steering system 24 may not include a steering wheel and / or steering column. The steering system 24 includes a steering column coupled, for example, by a rack and pinion or other mechanism (not shown), to an axle 50 associated with the front wheels 16. Alternatively, the steering system 24 may include a steer-by-wire system comprising actuators associated with each of the front wheels 16.

[0033] The sensor system 28 includes one or more detection devices 40a-40n that detect observable conditions of the external environment and / or the internal environment of the vehicle 10. The detection devices 40a-40n may include, among others, radars, lidar, global positioning systems, optical cameras, thermal imaging cameras, ultrasonic sensors, a steering wheel sensor, and / or other sensors.

[0034] The vehicle dynamics sensors provide vehicle dynamics data, including longitudinal speed, yaw rate, lateral acceleration, longitudinal acceleration, etc. The vehicle dynamics sensors may include wheel sensors that measure information relating to one or more wheels of the vehicle 10. In one embodiment, the wheel sensors comprise wheel speed sensors coupled to each of the wheels 16, 18 of the vehicle 10. Furthermore, the vehicle dynamics sensors 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 ​​for the vehicle 10, including lateral and longitudinal acceleration and yaw rate. In at least one embodiment, the vehicle dynamics sensors provide vehicle motion data.

[0035] The actuator system 30 includes one or more actuator devices 42a-42n that control one or more vehicle features, such as, among others, one or more vehicle wheels 16, 18, the drive system 20, the transmission system 22, the steering system 24, and the braking system 26. In various embodiments, the vehicle features may further include interior and / or exterior vehicle features, such as doors, a trunk, and cabin features such as air, music, lighting, etc. (not numbered).

[0036] The communication system 36 is configured to wirelessly communicate information to and from other entities 48, such as, among others, other vehicles (“V2V” communication), infrastructure (“V2I” communication), remote systems, and / or personal devices. In one exemplary embodiment, the communication system 36 is a wireless communication system configured to communicate via a wireless local area network (WLAN) using IEEE 802.11 standards or using cellular data communication. However, additional or alternative communication methods, such as a dedicated short-range communication (DSRC) channel, are also considered within the scope of this disclosure.DSRC channels refer to one-way or two-way short-range to medium-range wireless communication channels specifically designed for automotive use and a corresponding set of protocols and standards.

[0037] The data storage device 32 stores data for use in the ADS of the vehicle 10. In various embodiments, the data storage device 32 stores defined maps of the navigable environment. In various embodiments, the defined maps can be predefined by and received from a remote system. For example, the defined maps can be compiled by the remote system and communicated to the vehicle 10 (wirelessly and / or via a wired connection) and stored in the data storage device 32. It is understood that the data storage device 32 can be part of the controller 34, separate from the controller 34, or part of the controller 34 and part of a separate system.

[0038] The controller 34 includes at least one processor 44 and a computer-readable storage device or media 46. The processor 44 may be any custom-made or commercially available processor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processor among several processors associated with the controller 34, a microprocessor-based microprocessor (in the form of a microchip or chipset), a macroprocessor, any combination thereof, or generally any device for executing instructions. The computer-readable storage device or media 46 may include volatile and nonvolatile storage in read-only memory (ROM), random-access memory (RAM), and keep-alive memory (KAM), for example.KAM is a persistent or non-volatile memory that can be used to store various operating variables while the processor 44 is powered off. The computer-readable memory device or media 46 can be implemented using any number of known memory devices, such as PROMs (programmable read-only memory), EPROMs (electrical PROMs), EEPROMs (electrically erasable PROMs), flash memory, or any other electrical, magnetic, optical, or combined memory devices capable of storing data, some of which represent executable instructions used by the controller 34 in controlling the vehicle 10. In at least one embodiment, the computer-readable memory device 46 is at least one memory configured to store the cold-start emission attenuation system 100.

[0039] The instructions can include one or more separate programs, each comprising an ordered list of executable instructions for implementing logical functions. When executed by the processor 44, the instructions receive and process signals from the sensor system 28, perform logic, calculations, procedures, and / or algorithms to automatically control the components of the vehicle 10, and generate control signals to the actuator system 30 to automatically control the components of the vehicle 10 based on the logic, calculations, procedures, and / or algorithms. Although in Fig. While only one controller 34 is shown in Figure 1, embodiments of the vehicle 10 may include any number of controllers 34 that communicate via any suitable communication medium or combination of communication media and that interact to process the sensor signals, perform logic, calculations, procedures and / or algorithms, and generate control signals to automatically control features of the vehicle 10. In various embodiments, the controller(s) 34 are configured to implement ADS.

[0040] With reference to Fig. Figure 2 shows a functional block diagram of a controller 34 that includes a cold-start emission mitigation system 100 according to at least one embodiment. 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 that includes one or more instructions stored in or assigned to the at least one memory 46. The at least one memory 46 contains instructions that the at least one processor 44 is configured to execute. The at least one memory 46 includes an embodiment of the cold-start emission mitigation system 100, which is configured to mitigate cold-start emissions by managing the turbocharger turbine speed. In at least one embodiment, the cold-start emission mitigation system 100 includes a turbine speed manager 200.In at least one embodiment, the cold-start emission attenuation system 100 includes the turbine speed manager 200 and a turbine model 202. The controller 34 is configured to communicate with an ignition switch 204, a turboshaft actuator 206, one or more oxygen sensors 208, and a wastegate actuator 210. The controller 34 may include additional components that facilitate the operation of the cold-start emission attenuation system 100. The operation of the cold-start emission attenuation system 100 is described in more detail below.

[0041] With reference to Fig. Figure 3 shows a functional block diagram of an internal combustion engine system 300 according to at least one embodiment. 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 the oxygen sensor(s) 208. The catalyst start-up temperature is determined based on oxygen sensor data received by the oxygen sensor(s) 208. The conversion of the exhaust gas into hydrocarbons and nitrogen oxides is determined via the oxygen content.

[0042] The internal combustion engine system 300 can include additional components that facilitate the operation of the internal combustion engine system 300.

[0043] Compressor 310 draws in ambient air 316 and produces compressed air 318. Engine 304 receives the compressed air 318. Fuel 320 is injected into engine 304. The compressed air 318 and the fuel 320 combine to form an air-fuel mixture, which is used in a combustion process by engine 304. Exhaust gas 322 is produced by engine 304 as a byproduct of the combustion process. The cold start emission control system 100 sends a command to the wastegate actuator 210 to place the wastegate 306 in a fully open position.

[0044] A first part of the exhaust gas 324, generated by the engine 304, passes through the turbine 312 to the catalyst block 308. A second part of the exhaust gas 326, also generated by the engine 304, bypasses the turbine 312 and passes through the wastegate 306 to the catalyst block 308. The first part of the exhaust gas 324 and the second part of the exhaust gas 326 are processed by the catalyst block 308 before being released as emissions 328 into the outside environment, for example, via the rear of the vehicle 10.

[0045] The vehicle 10 relies on the catalyst block 308 to process the first and second parts of the exhaust gas 324, 326 before releasing the processed exhaust gas as emissions 328 from the vehicle 10. Catalyst blocks 308 typically need to reach an operating temperature, such as 500 °C, to effectively process the exhaust gas 324, 326. The operating temperature of the catalyst block 308 is referred to as the catalyst start-up temperature. In at least one embodiment, the catalyst start-up temperature is a value that lies somewhere in the middle of a catalyst start-up temperature range. A cold start of an internal combustion engine system 300 occurs when a vehicle 10 is started after the engine 304 has been switched off for several hours. During a cold start, the vehicle 10 may emit excessive emissions 328 until the catalyst block 308 reaches the catalyst start-up temperature.

[0046] The cold start emission attenuation system 100 is configured to manage the rotational speed of the turbine 312 via the turboshaft actuator 206 to accelerate the process of the catalyst block 308 reaching the catalyst start-up temperature, thereby attenuating cold start emissions 328. The cold start emission attenuation system 100 manages the rotation of the turbine 312 to reduce the heat transferred from the initial portion of the exhaust gas 324 to the exhaust system walls before the exhaust gas 324 reaches the catalyst block 308, thus retaining as much heat as possible to warm the catalyst block 308.

[0047] With reference to Fig. Figure 4 shows a flowchart representation of an exemplary method 400 for mitigating cold-start emissions by implementing a zero turbine speed of a turbine 312 according to at least one embodiment. The method 400 is described with reference to an exemplary implementation of an embodiment of a cold-start emission mitigation system 100. As can be seen from the disclosure, the order of operation within the method 400 is not limited to sequential execution, as shown in Figure 4. Fig. 4 illustrates, but can be carried out in one or more different sequences as required and in accordance with the present disclosure.

[0048] In embodiment 402, the cold start emission reduction system 100 receives an ignition activation signal from the ignition switch 204 of the vehicle 10. In at least one embodiment, the turbine speed controller 200 receives the ignition activation signal from the ignition switch 204 of the vehicle 10. The ignition activation signal is generated in response to the activation of the ignition switch 204 to start the engine 304. The ignition switch 204 is defined as a switch used to start non-diesel and diesel engines.

[0049] The wastegate 306 is a valve that controls the portion of the exhaust gas 324 that flows to the turbine 312 and the portion of the exhaust gas 326 that bypasses the turbine 312 and flows directly to the catalyst block 308. At 404, the cold start emission control system 100 issues a command to the wastegate actuator 210 to open the wastegate 306. In at least one embodiment, the cold start emission control system 100 issues the command to the wastegate actuator 210 to partially open the wastegate 306. In at least one embodiment, the cold start emission control system 100 issues the command to the wastegate actuator 210 to fully open the wastegate 306. In at least one embodiment, the turbine speed manager 200 issues a command to the wastegate actuator 210 to open the wastegate 306. In at least one embodiment, the turbine speed manager 200 issues a command to the wastegate actuator 210 to partially open the wastegate 306.In at least one embodiment, the turbine speed manager 200 issues the command to the wastegate actuator 210 to fully open the wastegate 306.

[0050] When the exhaust gas 322 is released by the engine 304 after a combustion process, the exhaust gas 322 has an engine exhaust gas temperature. The portion of the exhaust gas 324 that flows through the turbine 312 experiences heat loss as it passes through the turbine 312 and has a turbine exhaust gas temperature. The turbine exhaust gas temperature of the exhaust gas 324 after it has passed through the turbine 312 is lower than the engine exhaust gas temperature of the exhaust gas 322 released by the engine 304.

[0051] The portion of the exhaust gas 326 that bypasses the turbine 312 and flows through the wastegate 306 has a temperature close to that of the engine exhaust gas 322 released by the engine 304. Opening the wastegate 306 allows a stream of exhaust gas 326, at the engine exhaust gas temperature, to flow through the wastegate 306 and directly to the catalyst block 308 to heat it.

[0052] Since the exhaust gas 326 flowing through the wastegate 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 wastegate 306 to the catalyst block 308 allows the catalyst block 308 to reach the catalyst start-up temperature in less time than if all the exhaust gas 322 generated by the engine 304 were routed through the turbine 312 to the catalyst block 308.

[0053] At 406, the cold-start emission control system 100 issues a command to the turboshaft actuator 206 to implement zero turbine speed of the turbine 312. In at least one embodiment, the turbine speed manager 200 issues the command to the turboshaft actuator 206 to implement zero turbine speed of a turbine 312. In at least one embodiment, the turboshaft actuator 206 is a mechanical braking system that clamps and holds the turboshaft 314 in place to prevent rotation of the turbine 312 in response to the command. In at least one embodiment, the turboshaft actuator 206 is a motor-generator unit (MGU). The MGU generates the clamping force to prevent rotation of the turbine 312 in response to the command.

[0054] The portion of the exhaust gas 324 that passes through the turbine 312 experiences a temperature drop as it passes through the turbine 312. The portion of the exhaust gas 324 has the engine exhaust gas temperature as it enters the turbine 312, and the turbine exhaust gas temperature as it exits the turbine 312. The turbine exhaust gas temperature is lower than the engine exhaust gas temperature.

[0055] If the turbine 312 is allowed to rotate at a standard turbine speed while the portion of the exhaust gas 324 passes through the turbine 312, that portion of the exhaust gas 324 will have a standard turbine exhaust gas temperature as it exits the turbine 312. The standard turbine exhaust gas temperature is lower than the engine exhaust gas temperature.

[0056] When the turboshaft actuator 206 clamps and holds the turboshaft 314 in place to prevent the turbine 312 from rotating, the portion of the exhaust gas 324 may have an elevated turbine exhaust gas temperature as it exits the turbine 312. This elevated turbine exhaust gas temperature may be lower than the engine exhaust gas temperature and higher than the standard turbine exhaust gas temperature. The turbine outlet vortex associated with the portion of the exhaust gas 324 exiting the turbine 312 is lower when the turbine 312's rotation is prevented. The lower vortex means that less heat is absorbed at the exhaust gas walls.

[0057] When the portion of the exhaust gas 324 exhibiting the elevated turbine exhaust gas temperature flows from the turbine 312 to the catalyst block 308, the elevated turbine exhaust gas temperature heats the catalyst block 308 at a faster rate than if the portion of the exhaust gas 324 exhibited the standard turbine exhaust gas temperature associated with flowing through the turbine 312 rotating at the standard turbine speed. The flow of the portion of the exhaust gas 324 exhibiting the elevated turbine exhaust gas temperature to the catalyst block 308 allows the catalyst block 308 to reach the catalyst start-up temperature in a shorter time than the flow of the initial portion of the exhaust gas 324 exhibiting the standard turbine exhaust gas temperature to the catalyst block 308.

[0058] In 408, the cold start emission attenuation system 100 determines the catalyst temperature of the catalyst block 308 based on oxygen sensor data received by the oxygen sensor(s) 208 associated with the catalyst block 308. In at least one embodiment, the turbine speed manager 200 determines the catalyst temperature of the catalyst block 308 based on oxygen sensor data received by the oxygen sensor(s) 208 associated with the catalyst block 308. The catalyst temperature sensor 208 provides the catalyst temperature of the catalyst block 308.

[0059] At step 410, the cold-start emission attenuation system 100 determines whether the catalyst temperature is higher than the catalyst start-up temperature. In at least one embodiment, the turbine speed manager 200 determines whether the catalyst temperature is higher than the catalyst start-up temperature. If it is determined that the catalyst temperature is not higher than the catalyst start-up temperature, step 410 is repeated. If it is determined that the catalyst temperature is higher than the catalyst start-up temperature, the cold-start emission attenuation system 100 issues a command to the turboshaft actuator 206 to release the turboshaft 314 from jamming and allow the turbine 312 to rotate at standard turbine speed at step 412.In at least one embodiment, when it is determined that the catalyst temperature is greater than the catalyst start-up temperature, the turbine speed manager 200 issues the command to the turboshaft actuator 206 to release the clamping of the turboshaft 314 and to allow the turbine 312 to rotate at 412 at the standard turbine speed.

[0060] With reference to Fig. Figure 5 is a flowchart representation of an exemplary method 500 for attenuating cold-start emissions by implementing a turbine speed based on turbine outlet turbulence according to at least one embodiment. The method 500 is described with reference to an exemplary implementation of an embodiment of a cold-start emission attenuation system 100. As can be seen from the disclosure, the order of operation within the method 500 is not limited to sequential execution, as shown in Figure 5. Fig. 5 illustrates, but can be carried out in one or more different sequences as required and in accordance with the present disclosure.

[0061] In embodiment 502, the cold start emission reduction system 100 receives an ignition activation signal from the ignition switch 204 of the vehicle 10. In at least one embodiment, the turbine speed controller 200 receives the ignition activation signal from the ignition switch 204 of the vehicle 10. The ignition activation signal is generated in response to the activation of the ignition switch 204 to start the engine 304. The ignition switch 204 is defined as a switch used to start non-diesel and diesel engines.

[0062] The wastegate 306 is a valve that controls the portion of the exhaust gas 324 that flows to the turbine 312 and the portion of the exhaust gas 326 that bypasses the turbine 312 and flows directly to the catalyst block 308. At 504, the cold start emission control system 100 issues a command to the wastegate actuator 210 to open the wastegate 306. In at least one embodiment, the cold start emission control system 100 issues the command to the wastegate actuator 210 to partially open the wastegate 306. In at least one embodiment, the cold start emission control system 100 issues the command to the wastegate actuator 210 to fully open the wastegate 306. In at least one embodiment, the turbine speed manager 200 issues a command to the wastegate actuator 210 to open the wastegate 306. In at least one embodiment, the turbine speed manager 200 issues a command to the wastegate actuator 210 to partially open the wastegate 306.In at least one embodiment, the turbine speed manager 200 issues the command to the wastegate actuator 210 to fully open the wastegate 306.

[0063] When the exhaust gas 322 is released by the engine 304 after a combustion process, the exhaust gas 322 has an engine exhaust gas temperature. The portion of the exhaust gas 324 that flows through the turbine 312 experiences heat loss as it passes through the turbine 312 and has a turbine exhaust gas temperature. The turbine exhaust gas temperature of the exhaust gas 324 after it has passed through the turbine 312 is lower than the engine exhaust gas temperature of the exhaust gas 322 released by the engine 304.

[0064] The portion of the exhaust gas 326 that bypasses the turbine 312 and flows through the wastegate 306 has a temperature close to that of the engine exhaust gas 322 released by the engine 304. Opening the wastegate 306 allows a stream of exhaust gas 326, at the engine exhaust gas temperature, to flow through the wastegate 306 and directly to the catalyst block 308 to heat it.

[0065] Since the exhaust gas 326 flowing through the wastegate 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 wastegate 306 to the catalyst block 308 allows the catalyst block 308 to reach the catalyst start-up temperature in less time than if all the exhaust gas 322 generated by the engine 304 were routed through the turbine 312 to the catalyst block 308.

[0066] At 506, the turbine speed manager 200 issues a command to the turboshaft actuator 206 to implement a modified turbine speed for turbine 312. The turbine speed manager 200 receives the modified turbine speed from turbine model 202. Turbine model 202 determines the modified turbine speed for turbine 312 based on the turbine outlet vortex. A portion of the exhaust gas 324 flows through turbine 312 and exits at a turbine outlet. This portion of the exhaust gas 324 exhibits a turbine outlet vortex as it exits the turbine outlet. The turbine outlet vortex is turbulence resulting from the portion of the exhaust gas 324 flowing through turbine 312. The turbine outlet vortex causes a temperature drop in the part of the exhaust gas 324 as it flows from the turbine outlet to the catalyst block 308.

[0067] The turbine outlet vortex exhibits a standard turbine outlet vortex resulting from the portion of the exhaust gas 324 that flows through the turbine 312 while the turbine 312 is rotating at a standard turbine speed. The portion of the exhaust gas 324 exhibits a standard turbine exhaust gas temperature as it reaches the catalyst block 308. The standard turbine exhaust gas temperature is based on the standard turbine outlet vortex.

[0068] The turbine model 202 is configured to determine a turbine outlet vortex at zero turbine speed, which is associated with holding the turbine 312 at zero turbine speed while the exhaust gas 324 flows through the turbine 312. When the portion of the exhaust gas 324 flows through the turbine 312 while the turbine 312 is held at zero turbine speed, the exhaust gas 324 has an exhaust gas temperature at zero turbine outlet speed when the portion of the exhaust gas 324 reaches the catalyst block 308.

[0069] Turbine model 202 is configured to determine a modified turbine speed for turbine 312, which generates a reduced turbine outlet vortex. The reduced turbine outlet vortex is smaller than both the turbine outlet vortex at zero turbine speed and the standard turbine outlet vortex. The modified turbine speed is designed to counteract the turbine outlet vortex at zero turbine speed, so that the reduced turbine outlet vortex generated at the modified turbine speed is as low as possible. When the portion of exhaust gas 324 flows through turbine 312 while turbine 312 is rotating at the modified turbine speed, the reduced turbine outlet vortex causes the exhaust gas 324 to have an increased turbine exhaust gas temperature as it reaches the catalyst block 308.The increased turbine exhaust temperature is higher than the standard turbine exhaust temperature and the exhaust temperature at a turbine outlet speed of zero. When the portion of the exhaust gas 324 exhibiting the increased turbine exhaust temperature reaches the catalyst block 308, the increased turbine exhaust temperature heats the catalyst block 308 at a faster rate than if the portion of the exhaust gas 324 were at the standard turbine exhaust temperature.

[0070] In at least one embodiment, the turbine model 202 is trained before installation in the vehicle 10 using engine test data associated with the internal combustion engine system 300. In at least one embodiment, the turbine model 202 is a mathematical model configured to calculate the adapted turbine speed. In at least one embodiment, the turbine model 202 is configured to generate the adapted turbine speed partly based on one or more of the exhaust gas flow rate of the portion of the exhaust gas 324, an exhaust gas temperature, a turbine fan blade configuration of the turbine 312, and an altitude of the vehicle 10.

[0071] In 508, the cold start emission attenuation system determines the catalyst temperature of the catalyst block 308 based on oxygen sensor data received by the oxygen sensor(s) 208 associated with the catalyst block 308. In at least one embodiment, the turbine speed manager 200 determines the catalyst temperature of the catalyst block 308 based on oxygen sensor data received by the oxygen sensor(s) 208 associated with the catalyst block 308.

[0072] At 510, the cold start emission attenuation system 100 determines whether the catalyst temperature is higher than the catalyst start-up temperature. In at least one embodiment, the turbine speed manager 200 determines whether the catalyst temperature is higher than the catalyst start-up temperature. If it is determined that the catalyst temperature is not higher than the catalyst start-up temperature, 510 is repeated. If it is determined that the catalyst temperature is higher than the catalyst start-up temperature, the cold start emission attenuation system 100 issues a command to the turboshaft actuator 206 to rotate the turbine 312 at 512 at the standard turbine speed.In at least one embodiment, when it is determined that the catalyst temperature is greater than the catalyst start-up temperature, the turbine speed manager 200 issues the command to the turboshaft actuator 206 to rotate the turbine 312 at 512 at the standard turbine speed.

[0073] With reference to Fig. Figure 6 shows a flowchart representation of an exemplary method 600 for managing cold-start emissions by implementing a turbine speed based on exhaust gas expansion according to at least one embodiment. The method 600 is described with reference to an exemplary implementation of an embodiment of a cold-start emission mitigation system 100. As can be seen from the disclosure, the order of operation within the method 600 is not limited to sequential execution, as shown in Figure 6. Fig.6 illustrates, but can be carried out in one or more different sequences as required and in accordance with the present disclosure.

[0074] In embodiment 602, the cold start emission reduction system 100 receives an ignition activation signal from the ignition switch 204 of the vehicle 10. In at least one embodiment, the turbine speed controller 200 receives the ignition activation signal from the ignition switch 204 of the vehicle 10. The ignition activation signal is generated in response to the activation of the ignition switch 204 to start the engine 304. The ignition switch 204 is defined as a switch used to start non-diesel and diesel engines.

[0075] The wastegate 306 is a valve that controls the portion of the exhaust gas 324 flowing to the turbine 312 and the portion of the exhaust gas 326 bypassing the turbine 312 and flowing directly to the catalyst block 308. At 604, the cold start emission attenuation system 100 issues a command to the wastegate actuator 210 to open the wastegate 306. In at least one embodiment, the cold start emission attenuation system 100 issues the command to the wastegate actuator 210 to partially open the wastegate 306. In at least one embodiment, the cold start emission attenuation system 100 issues the command to the wastegate actuator 210 to fully open the wastegate 306. In at least one embodiment, the turbine speed manager 200 issues a command to the wastegate actuator 210 to open the wastegate 306. In at least one embodiment, the turbine speed manager 200 issues a command to the wastegate actuator 210 to partially open the wastegate 306.In at least one embodiment, the turbine speed manager 200 issues the command to the wastegate actuator 210 to fully open the wastegate 306.

[0076] When the exhaust gas 322 is released by the engine 304 after a combustion process, the exhaust gas 322 has an engine exhaust gas temperature. The portion of the exhaust gas 324 that flows through the turbine 312 experiences heat loss as it passes through the turbine 312 and has a turbine exhaust gas temperature. The turbine exhaust gas temperature of the exhaust gas 324 after it has passed through the turbine 312 is lower than the engine exhaust gas temperature of the exhaust gas 322 released by the engine 304.

[0077] The portion of the exhaust gas 326 that bypasses the turbine 312 and flows through the wastegate 306 has a temperature close to that of the engine exhaust gas 322 released by the engine 304. Opening the wastegate 306 allows a stream of exhaust gas 326, at the engine exhaust gas temperature, to flow through the wastegate 306 and directly to the catalyst block 308 to heat it.

[0078] Since the exhaust gas 326 flowing through the wastegate 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 wastegate 306 to the catalyst block 308 allows the catalyst block 308 to reach the catalyst start-up temperature in less time than if all the exhaust gas 322 generated by the engine 304 were routed through the turbine 312 to the catalyst block 308.

[0079] At 606, the turbine speed manager 200 issues a command to the turboshaft actuator 206 to implement an adjusted turbine speed for turbine 312. The turbine speed manager 200 receives the adjusted turbine speed from turbine model 202. Turbine model 202 determines the adjusted turbine speed for turbine 312 based on exhaust gas expansion. A portion of the exhaust gas 324 flows through turbine 312 and exits at a turbine outlet. This portion of the exhaust gas 324 exhibits exhaust gas expansion as it exits the turbine outlet. This exhaust gas expansion results from the portion of the exhaust gas 324 that flows through turbine 312. The exhaust gas expansion causes a temperature drop in the part of the exhaust gas 324 as it flows from the turbine outlet to the catalyst block 308.

[0080] The exhaust gas expansion exhibits a standard exhaust gas expansion resulting from the portion of the exhaust gas 324 that flows through the turbine 312 while the turbine 312 is rotating at a standard turbine speed. The portion of the exhaust gas 324 exhibits a standard turbine exhaust gas temperature as it reaches the catalyst block 308. The standard turbine exhaust gas temperature is based on the standard exhaust gas expansion.

[0081] Turbine model 202 is configured to determine a modified turbine speed for turbine 312, which produces reduced exhaust gas expansion. The reduced exhaust gas expansion is smaller than the standard exhaust gas expansion. The modified turbine speed is lower than the standard turbine speed and is designed to minimize exhaust gas expansion. When the portion of exhaust gas 324 flows through turbine 312 while turbine 312 is rotating at the modified turbine speed, the reduced exhaust gas expansion causes exhaust gas 324 to have an increased turbine exhaust gas temperature as it reaches the catalyst block 308. The increased turbine exhaust gas temperature is higher than the standard turbine exhaust gas temperature.When the portion of the exhaust gas 324, which has the increased turbine exhaust gas temperature, reaches the catalyst block 308, the increased turbine exhaust gas temperature heats the catalyst block 308 at a faster rate than if the portion of the exhaust gas 324 had the standard turbine exhaust gas temperature.

[0082] In at least one embodiment, the turbine model 202 is trained before installation in the vehicle 10 using engine test data associated with the internal combustion engine system 300. In at least one embodiment, the turbine model 202 is a mathematical model configured to calculate the adapted turbine speed. In at least one embodiment, the turbine model 202 is configured to generate the adapted turbine speed partly based on one or more of the exhaust gas flow rate of the portion of the exhaust gas 324, an exhaust gas temperature, a turbine fan blade configuration of the turbine 312, and an altitude of the vehicle 10. In at least one embodiment, the standard exhaust gas expansion and the reduced exhaust gas are partly based on an exhaust gas flow rate from an exhaust manifold of the vehicle 10 to the turbine 312.

[0083] In 608, the cold start emission attenuation system determines the catalyst temperature of the catalyst block 308 based on oxygen sensor data received by the oxygen sensor(s) 208 associated with the catalyst block 308. In at least one embodiment, the turbine speed manager 200 determines the catalyst temperature of the catalyst block 308 based on oxygen sensor data received by the oxygen sensor(s) 208 associated with the catalyst block 308.

[0084] At 610, the cold start emission attenuation system 100 determines whether the catalyst temperature is higher than the catalyst start-up temperature. In at least one embodiment, the turbine speed manager 200 determines whether the catalyst temperature is higher than the catalyst start-up temperature. If it is determined that the catalyst temperature is not higher than the catalyst start-up temperature, 610 is repeated. If it is determined that the catalyst temperature is higher than the catalyst start-up temperature, the cold start emission attenuation system 100 issues a command to the turboshaft actuator 206 to rotate the turbine 312 at 612 at the standard turbine speed.In at least one embodiment, when it is determined that the catalyst temperature is greater than the catalyst start-up temperature, the turbine speed manager 200 issues the command to the turboshaft actuator 206 to rotate the turbine 312 at 612 at the standard turbine speed.

[0085] In at least one embodiment, the turbine model 202 is configured to determine a first turbine outlet vortex of the exhaust gas 324 resulting from the exhaust gas 324 flowing through the turbine 312 while the turbine 312 is held at a turbine speed of zero. The turbine model 202 is configured to determine a first exhaust gas expansion resulting from the exhaust gas 324 flowing through the turbine 312 while the turbine is rotated at the standard turbine speed. The turbine model 202 is configured to generate the adapted turbine speed based on the first turbine outlet vortex such that it is lower than the standard turbine speed. The second turbine outlet vortex of the exhaust gas 324 resulting from the exhaust gas 324 flowing through the turbine 312 while the turbine 312 is rotated at the adapted turbine speed is smaller than the first turbine outlet vortex.A second exhaust gas expansion, resulting from the exhaust gas 324 flowing through the turbine 312 while the turbine 312 is rotated at the first turbine speed, is smaller than the first exhaust gas expansion.

Claims

[1] Method (400) for reducing cold start emissions produced by a vehicle (10), comprising: Receiving (402), at a control unit (34), an ignition signal from an ignition switch (204) of the vehicle (10); Output (406), by means of the control (34), of a first control signal to a turboshaft actuator (206) to rotate a turbine (312) of a turbocharger (302) of the vehicle (10) at a first turbine speed in response to the ignition switch-on signal, wherein the first turbine speed differs from a standard turbine speed associated with the ignition switch-on signal, wherein: A rotation of the turbine (312) at the standard turbine speed results in an exhaust gas (324) having an initial exhaust gas temperature after the exhaust gas (324) passes through the turbine (312) to a catalyst block (308) of the vehicle (10), a rotation of the turbine (312) at the first turbine speed results in the exhaust gas (324) having a second exhaust gas temperature after the exhaust gas (324) passes through the turbine (312) to the catalyst block (308), and the second exhaust gas temperature is higher than the first exhaust gas temperature; Received at the control unit (34) from oxygen sensor data assigned to the catalyst block (308) from an oxygen sensor (208); Determining (408) a catalyst temperature based on the oxygen sensor data, Determine (410), by means of the control (34), whether the catalyst temperature is greater than a catalyst start-up temperature; and Output, by the control unit (34), a second control signal to the turboshaft actuator (206) to rotate the turbine based on the determination at the standard speed; and Output of the first control signal by the controller (34) to the turboshaft actuator (206) to rotate the turbine (312) at the first turbine speed, where the first turbine speed is zero and the turboshaft actuator (206) prevents the rotation of the turbine (312) in response to the first control signal. [2] Method (400) according to claim 1, further comprising receiving, at the control (34), the first turbine speed from a turbine model (202), wherein the turbine model (202) is configured to: Determining a first turbine outlet vortex of the exhaust gas resulting from the exhaust gas (324) flowing through the turbine (312) while the turbine (312) is held at a turbine speed of zero, and Generating the first turbine speed based on the first turbine outlet vortex, wherein a second turbine outlet vortex of the exhaust gas resulting from the exhaust gas (324) flowing through the turbine (312) while the turbine (312) is rotated at the first turbine speed is smaller than the first turbine outlet vortex. [3] Method (400) according to claim 1, further comprising receiving, at the control (34), the first turbine speed from a turbine model (202), wherein the turbine model (202) is configured to: Determining an initial exhaust gas expansion resulting from the exhaust gas (324) flowing through the turbine (312) while the turbine (312) is rotated at the standard turbine speed, and Generating the first turbine speed such that it is smaller than the standard turbine speed, wherein a second exhaust gas expansion resulting from the exhaust gas (324) flowing through the turbine (312) while the turbine (312) is rotated at the first turbine speed is smaller than the first exhaust gas expansion. [4] Method (400) according to claim 3, wherein the first exhaust gas expansion and the second exhaust gas expansion are partially based on an exhaust gas flow rate from an exhaust manifold of an engine (304) to the turbine (312). [5] Method (400) according to claim 1, further comprising receiving, at the control (34), the first turbine speed from a turbine model (202), wherein the turbine model (202) is configured to: Determining a first turbine outlet vortex of the exhaust gas resulting from the exhaust gas (324) flowing through the turbine (312) while the turbine (312) is held at a turbine speed of zero, Determining an initial exhaust gas expansion resulting from the exhaust gas (324) flowing through the turbine (312) while the turbine (312) is rotated at the standard turbine speed, and Generating the first turbine speed based on the first turbine outlet vortex and in such a way that it is lower than the standard turbine speed, where: a second turbine outlet vortex of the exhaust gas, resulting from the exhaust gas (324) flowing through the turbine (312) while the turbine (312) is rotated at the first turbine speed, is smaller than the first turbine outlet vortex, and a second exhaust gas expansion, resulting from the exhaust gas (324) flowing through the turbine (312) while the turbine (312) is rotated at the first turbine speed, is smaller than the first exhaust gas expansion. [6] Method (400) according to claim 1, further comprising receiving, at the control (34), the first turbine speed from a turbine model (202), wherein the turbine model (202) is configured to generate the first turbine speed based on at least one of an exhaust flow rate, an exhaust temperature, a turbine fan blade configuration and a height of the vehicle (10). [7] Method (400) according to claim 1, further comprising outputting a third control signal by the control unit (34) to a wastegate actuator (210) to open a wastegate (306) to allow part of the exhaust gas to bypass the turbine (312) and flow from an exhaust manifold of the vehicle (10) via the wastegate (306) to the catalyst block (308). [8] Method (400) according to claim 1, further comprising outputting, by means of the control (34), the first control signal and the second control signal to the turbo shaft actuator (206) via a motor generator unit, MGU. [9] System (100) for reducing cold start emissions produced by a vehicle (10), comprising: at least one processor (44); and at least one memory (46) that is communicatively coupled to the at least one processor (44), wherein the at least one memory (46) comprises instructions which, when executed by the at least one processor (44), cause the at least one processor (44) to do the following: Receiving an ignition switch signal from an ignition switch (204) of the vehicle (10); Outputting a first control signal to a turboshaft actuator (206) to rotate a turbine (312) of a turbocharger (302) of the vehicle (10) at a first turbine speed in response to the ignition switch-on signal, wherein the first turbine speed differs from a standard turbine speed associated with the ignition switch-on signal, wherein: A rotation of the turbine (312) at the standard turbine speed results in an exhaust gas (324) having an initial exhaust gas temperature after the exhaust gas (324) passes through the turbine (312) to a catalyst block (308) of the vehicle (10), a rotation of the turbine (312) at the first turbine speed results in the exhaust gas (324) having a second exhaust gas temperature after the exhaust gas (324) passes through the turbine (312) to the catalyst block (308), and the second exhaust gas temperature is higher than the first exhaust gas temperature; Receiving oxygen sensor data assigned to the catalyst block (308) from an oxygen sensor (208); Determining a catalyst temperature based on oxygen sensor data; determining whether the catalyst temperature is higher than a catalyst start-up temperature; and Outputting a second control signal to the turboshaft actuator (206) to rotate the turbine (312) based on the determination at the standard speed; and Output of the first control signal by the controller (34) to the turboshaft actuator (206) to rotate the turbine (312) at the first turbine speed, where the first turbine speed is zero and the turboshaft actuator (206) prevents the rotation of the turbine (312) in response to the first control signal.

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