System for improving the stopping and starting of a turbocharged engine

Abstract

Power engine system comprising the following: a power machine (10); a turbocharger coupled to the power unit (10), the turbocharger comprising adjustable turbine blades (230); and a controller (12) configured to adjust a turbine blade position to an increasingly closed position in response to a request to stop the engine (10) in order to increase the exhaust back pressure of the engine (10), characterized in that a time of the request to stop the power machine (10), and a time of adjusting the turbine blade position to an increasingly closed position equal to a first time point (T1, T 11 ) are and the controller (12) is further designed to control the adjustment to an increasingly closed position in such a way that the exhaust back pressure of the engine (10) increases briefly.

Description

[0001] Engines can be automatically stopped and started to save fuel. However, each automatic stop and start can increase the potential for higher engine emissions and driver dissatisfaction. For example, if an engine rotates longer than desired during a stop, it may pump air into the exhaust system, potentially impairing exhaust performance downstream of the exhaust system. Conversely, the engine speed may increase during a restart, resulting in more than the target torque being delivered to the vehicle's wheels. Consequently, automatic engine stop and start may improve fuel economy at the expense of engine emissions and driver satisfaction.

[0002] DE 10 2010 032 087 A1 discloses a device with the features of the preamble of claim 1. Another publication relevant to the prior art is DE 10 2010 014 331 A1.

[0003] The inventors herein have recognized the above-mentioned limitations and have developed an engine system according to claim 1; advantageous developments of the invention are described in the dependent claims. The engine system comprises: an engine; a turbocharger coupled to the engine, the turbocharger including adjustable turbine blades; and a controller including persistent instructions for adjusting a turbine blade position in response to a request to stop the engine, the position being adjusted to increase exhaust backpressure of the engine.

[0004] By adjusting the turbine blade position during engine shutdown, it is possible to reduce the time it takes for the engine to come to a complete stop. Consequently, the amount of air pumped by the engine during shutdown can be reduced. Furthermore, the turbine blades can be adjusted during engine startup to minimize engine speed overshoot. As a result, a specific torque value can be transmitted from the engine to the vehicle's wheels during automatic engine startup.

[0005] The described feature can offer several advantages. For example, it can reduce engine emissions during engine shutdown. Furthermore, it can improve engine startup. Finally, it can provide an enhanced driving experience for a vehicle that automatically stops and starts.

[0006] The above advantages and further advantages and features of the present description will be readily apparent from the following detailed description, whether taken alone or in conjunction with the accompanying drawings.

[0007] It should be self-evident that the above summary is provided to introduce, in simplified form, a selection of the concepts that are further described in the detailed description. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is clearly defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that eliminate all the disadvantages stated above or in any part of this disclosure. Fig. 1 shows a schematic representation of a power machine; Fig. 2 and Fig. 3 show example devices for adjusting the exhaust back pressure of the engine; Fig. 4 and Fig. 5 shows simulated start and stop sequences of the engine; Fig. 6 and Fig. 7 show block diagrams of an example system; and Fig. 8 and Fig. 9 show an example method for operating a prime mover.

[0008] The present description relates to stopping and starting a turbocharged engine. In one example, the turbocharged engine may be stopped in a manner that may reduce an amount of oxygen delivered to an exhaust after a treatment device. In another example, the turbocharged engine is started in a manner that may enhance a driver's driving experience. Example systems may implement the Fig. 1-3 shown features in accordance with the block diagrams according to the Fig. 6 and Fig. 7. The engine and turbocharger can be operated to perform the operations according to the Fig. 4 and Fig. 5 about the in the Fig. 8 and Fig. nine methods are to be provided. In one example, the method involves adjusting the turbine blades to increase the back pressure of the engine exhaust system during engine stop and start.

[0009] In Fig. 1 is an internal combustion engine 10, comprising several cylinders, one of which is in Fig. 1, is controlled by an electronic engine controller 12. The engine 10 includes a combustion chamber 30 and cylinder walls 32, with a piston 36 positioned therein and connected to a crankshaft 40. The combustion chamber 30 is shown communicating with an intake manifold 44 and an exhaust manifold 48, respectively, via an intake valve 52 and an exhaust valve 54. Each intake and exhaust valve may be actuated by an intake cam 51 and an exhaust cam 53. The position of the intake cam 51 may be determined by the intake cam sensor 55. The position of the exhaust cam 53 may be determined by the exhaust cam sensor 57.

[0010] Fuel injector 66 is shown positioned to inject fuel directly into cylinder 30, known to those skilled in the art as direct injection. Alternatively, fuel may be injected into an intake port, known to those skilled in the art as port injection. Fuel injector 66 delivers liquid fuel proportional to a pulse width provided by controller 12. Fuel is delivered to fuel injector 66 by a fuel system (not shown) that includes a fuel tank, a fuel pump, and a fuel rail (not shown).

[0011] Air is supplied to the intake manifold 44 by a compressor 162. The exhaust gases rotate a turbine 164 coupled to a shaft 161, thereby driving the compressor 162. In some examples, a bypass passage 77 is included so that the exhaust gases can bypass the turbine 164 during select operating conditions. Flow through the bypass passage 77 is controlled via a wastegate valve 75. Further, a compressor bypass passage 86 may be provided in some examples to limit the pressure provided by the compressor 162. Flow through the bypass passage 86 is controlled via a valve 85. The intake manifold 44 is also shown communicating with a central throttle 62 that adjusts a position of a throttle plate 64 to control airflow from the engine's air intake 42. The central throttle valve 62 can be electrically operated.

[0012] The distributorless ignition system 88 provides a spark to the combustion chamber 30 via a spark plug 92 in response to the controller 12, in order to ignite the air-fuel mixture. In other examples, the engine can be a compression-ignition engine without an ignition system, such as a diesel engine. It is shown that a universal exhaust gas oxygen sensor (UEGO sensor) 126 is coupled to the exhaust manifold 48 upstream of a catalytic converter 70. Alternatively, the UEGO sensor 126 can be replaced by a dual-state exhaust gas oxygen sensor.

[0013] In one example, converter 70 may include multiple catalyst modules. In another example, multiple emission control devices, each with multiple modules, may be used. In one example, converter 70 may be a three-way catalyst.

[0014] The controller 12 is in Fig. 1 as a conventional microcomputer including: a microprocessor unit 102, input / output ports 104, a read-only memory 106, a random access memory 108, a latch 110, and a conventional data bus.It is shown that, in addition to the signals previously discussed, the controller 12 receives various signals from sensors coupled to the engine 10, including: an engine coolant temperature (ECT) from a temperature sensor 112 coupled to the cooling sleeve 114; a position sensor 134 coupled to an accelerator pedal 130 to sense the accelerator pedal position set by the foot 132; a measurement of the engine manifold pressure (MAP) from a pressure sensor 122 coupled to the intake manifold 44; an engine position sensor from a Hall effect sensor 118 sensing the position of the crankshaft 40; a measurement of the mass of air entering the engine from a sensor 120 (e.g., a hot-wire airflow meter); and a measurement of the throttle valve position from a sensor 58.Atmospheric pressure can also be sampled for processing by the controller 12 (the sensor is not shown). In a preferred aspect of the present description, the engine position sensor 118 generates a predetermined number of equally spaced pulses at each revolution of the crankshaft, from which the engine speed (RPM) can be determined.

[0015] In some examples, the power unit in a hybrid vehicle may be coupled to an electric motor / battery system. The hybrid vehicle may have a parallel configuration, a series configuration, or a variation or combination thereof. Furthermore, other power unit configurations may be used in some examples, such as a diesel engine.

[0016] During operation, each cylinder in the engine 10 typically goes through a four-stroke cycle: the cycle includes the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. Generally, during the intake stroke, the exhaust valve 54 is closed and the intake valve 52 is open. Air is introduced into the combustion chamber 30 via the intake manifold 44, with the piston 36 moving towards the bottom of the cylinder to increase the volume in the combustion chamber 30. The position in which the piston 36 is near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber 30 is at its largest volume) is typically referred to by those skilled in the field as bottom dead center (BDC). During the compression stroke, the intake valve 52 and the exhaust valve 54 are closed. The piston 36 moves towards the cylinder head to compress the air in the combustion chamber 30.The point at which the piston 36 is at the end of its stroke and closest to the cylinder head (e.g., when the combustion chamber 30 is at its smallest volume) is typically referred to by those skilled in the art as top dead center (TDC). In a process referred to herein as injection, fuel is introduced into the combustion chamber. In a process referred to herein as ignition, the injected fuel is ignited by known ignition means, such as a spark plug 92, resulting in combustion. During the power stroke, the expanding gases push the piston 36 back to BDC. The crankshaft 40 translates the piston motion into rotating shaft torque. Finally, during the exhaust stroke, the exhaust valve 54 is open to expel the combusted air-fuel mixture to the exhaust manifold 48, returning the piston to TDC.It should be noted that the above has been described only as an example and that the opening and / or closing times of the intake and exhaust valves may change, for example to provide positive or negative valve overlap, late closing of the intake valve, or various other examples.

[0017] In Fig. Figure 2 shows a cross-section of a first turbocharger for compressing the intake air of the engine and increasing the exhaust backpressure of the engine. The turbine 164 is shown to be mechanically coupled to the shaft 161. The compressor 162 is also shown to be mechanically coupled to the shaft 161. The shaft 161 is supported by the bearings 210, and the turbine blade position adjustment device 220 receives commands from the controller 12 to open or close the turbine blades 230.

[0018] During engine operation, exhaust gases act on the turbine 164 to cause it to rotate. The exhaust gases impart a force to the turbine blades 230 that can be varied depending on the position of the turbine blades 230. In one example, the exhaust gases impart greater force to the turbine blades 230 when the turbine blades are in a closed position. The exhaust gases impart less force to the turbine blades 230 when the turbine blades are in a fully open position. The turbine blades 230 can be varied to multiple positions between fully closed and fully open. The engine exhaust backpressure increases relative to the engine exhaust backpressure when the turbine blades are open and while the engine is operating at similar engine operating conditions.

[0019] In Fig. Figure 3 shows a cross-section of an alternative device 300 for compressing the intake air of the engine and increasing the exhaust back pressure of the engine. The components of the device 300, which have the same reference numerals as the components of the device shown in Figure 3, are shown in Figure 3. Fig. The devices shown in section 2 are the same as those shown in [reference to relevant document]. Fig. 2 are shown. Furthermore, the components with the same reference symbols operate in the same way as they do with respect to Fig. 2 has been discussed.

[0020] The device 300 is an electric machine comprising a first winding 320 and permanent magnets or a second winding 322. The controller 12 selectively supplies current to the winding 320 to generate a magnetic field that can increase or decrease the rotational resistance of the turbine 164, the shaft 161, and the compressor 162. The magnetic field generated by supplying current to the coil 320 interacts with a magnetic field of the shaft 161 generated by the permanent magnets or the windings 322. If the electric device 322 is a winding, current can be supplied to the winding to generate a magnetic field that interacts with the field generated by the winding 320.The two magnetic fields can act, depending on the current flow to the respective coils and the magnetic fields generated by the current or the permanent magnets, to both accelerate the shaft 161 and generate electrical energy from the shaft 161. The device 300 can also supply electrical energy to an electrical storage device (e.g., a battery, a capacitor, or a coil) when operated as a generator / three-phase generator.

[0021] Consequently, the system adjusts according to the Fig. 1-3 provides a power engine system comprising: a power engine; a turbocharger coupled to the power engine, the turbocharger containing adjustable turbine blades; and a controller containing continuous commands to adjust a turbine blade position in response to a request to stop the power engine, the position being adjusted to increase the exhaust backpressure of the power engine. In this way, the position of the turbine blades can be adjusted to control the speed of the power engine while the power engine is stopped.The engine system includes adjusting the position of the adjustable turbine blades to increase the exhaust backpressure of the engine by less than a threshold amount at a time before the last cylinder, which burns an air-fuel mixture prior to engine shutdown, draws in a quantity of air that participates in combustion after the engine shutdown request. The engine system also includes adjusting the position of the adjustable turbine blades at a time after the last cylinder, which burns an air-fuel mixture prior to engine shutdown, draws in a quantity of air.

[0022] In another example, the engine system includes at least partially opening the adjustable turbine buckets after the exhaust backpressure of the engine has been increased. The engine system includes where the at least partially opening the adjustable turbine buckets occurs in response to a change in operator intent condition. The engine system includes where the at least partially opening the adjustable turbine buckets is related to the period of engine stoppage. The engine system further includes a turbocharger turbine torque adjuster and additional instructions to increase a negative torque applied to the turbocharger by the turbocharger turbine torque adjuster.

[0023] The system according to the Fig. 1-3 also provides an engine system comprising: an engine; a turbocharger coupled to the engine, the turbocharger including adjustable turbine blades; and a controller including persistent instructions to adjust a turbine blade position in response to a request to stop the engine, wherein the turbine blade position is adjusted to increase engine exhaust backpressure during engine stoppage, and additional persistent instructions to increase engine exhaust backpressure during engine start-up via adjusting the turbine blade position. The engine system includes adjusting the blade position during engine start-up in response to an engine speed.The engine system includes adjusting the blade position to increase exhaust back pressure in response to an engine speed that is greater than the engine's set speed.

[0024] In another example, the engine system further includes an electrical device in electrical communication with the turbocharger turbine shaft. The engine system includes the electrical device being a motor, further including additional instructions to increase negative engine torque in response to the request to stop the engine. The engine system further includes additional instructions to increase negative engine torque during engine start-up. The engine system further includes additional instructions to adjust the negative engine torque in response to engine speed.

[0025] In Fig. Figure 4 shows a simulated operating sequence of the power machine. The operating sequence can be replicated by following the instructions of the procedure according to the Fig. 8 and Fig. 9 in the controller 12 of the Fig. The system described in sections 1-3 is provided. The vertical markers T0-T7 represent the points in time of particular interest during the process.

[0026] The first graphic representation from top to Fig. Figure 4 shows the rotational speed of the power engine against time. The Y-axis represents the rotational speed of the power engine, with the rotational speed increasing in the direction of the Y-axis arrow. The X-axis represents time, with time increasing from the left side of the Fig. 4 to the right of the Fig. 4 increases. The solid line 402 represents the line of the engine speed in accordance with the procedure according to the Fig. 8 and Fig. 9 during the current process. The dashed line 404 represents a line of the engine speed in accordance with the prior art procedures for starting and stopping the engine.

[0027] The second graphic representation from the top after Fig. Figure 4 shows the exhaust back pressure of the engine (e.g., the pressure that occurs in the exhaust ports of the engine cylinder and / or in the exhaust manifold 48). Fig. 1 developed) against time. The Y-axis represents the exhaust backpressure of the engine, with the exhaust backpressure of the engine increasing in the direction of the Y-axis arrow. The X-axis represents time, with time increasing from the left side of the Fig. 4 to the right side of the Fig. 4 increases. The solid line 408 represents the line of exhaust back pressure of the engine in accordance with the procedure according to the Fig. 8 and Fig. 9 during the current sequence. The dashed line 410 represents the engine exhaust backpressure line in accordance with prior art engine starting and stopping techniques.

[0028] The third graphic representation from the top after Fig. Figure 4 shows the turbine blade state of the turbocharger versus time. The Y-axis represents the state of the turbocharger blades, with the turbine blades being fully closed when the signal is at the X-axis level. The turbine blades are fully open when the signal is at a level near the Y-axis arrow. The X-axis represents time, with time being calculated from the left side of the Fig. 4 to the right of the Fig. 4 increases.

[0029] The fourth graphic representation from the top after Fig. Figure 4 shows a state of an engine stop / start command versus time. The Y-axis represents the state of the engine stop / start command, where the engine stop / start command indicates that the engine is running or is to be started when the engine stop / start command is at a higher level. The engine stop / start state indicates that the engine is stopped or is to be stopped when the engine stop / start command is at a lower level. The X-axis represents time, where time is from the left side of the Fig. 4 to the right side of the Fig. 4 increases.

[0030] At time T0, the engine is operating at a medium engine speed, with a medium exhaust backpressure. The turbocharger turbine blade state is at a medium level, indicating that the turbine blades are partially open. The engine stop / start command is at a higher level, indicating that the engine is running and not requesting a stop.

[0031] At time T1, a power machine stop request is activated and / or indicated by the state of the power machine stop / start command transitioning from a higher level to a lower level. The power machine stop / start request can be generated when a set of conditions for automatically stopping a power machine is met, without an operator directly requesting a stop via a dedicated input with a single function to stop and / or halt a power machine (e.g., an ignition switch). In this example, the power machine stop request is generated in response to a vehicle speed reaching zero, a driver depressing the brake pedal, and an accelerator pedal not being depressed.

[0032] The engine is stopped by halting the fuel flow and spark to the engine in response to the engine stop / start request, which transitions to a lower level. The turbine blade state is adjusted to an increasingly closed state in response to the engine stop / start request, which transitions to a lower level. In one example, the turbine blades are adjusted to an increasingly closed state after a cylinder has drawn in air for a final combustion event before the engine stops. In other examples, the adjustable turbine blades are set to increase the engine's exhaust backpressure by less than a threshold amount before a final cylinder, which burns an air-fuel mixture before the engine stops, draws in a significant amount of air.In this way, the last combustion event before the engine stops is not affected by adjusting the turbocharger blade position.

[0033] Engine exhaust backpressure briefly increases in response to adjusting the turbine bucket state to a more closed position. However, engine exhaust backpressure decreases as engine speed decreases. Further, engine exhaust backpressure of line 408 is greater than engine exhaust backpressure of line 410. By increasing engine exhaust backpressure, engine pumping work increases, thereby removing more kinetic energy from the rotating engine so that the engine stops faster, as indicated by engine speed line 402 decreasing faster than engine speed line 404.

[0034] Between time T1 and time T2, the engine speed decreases in response to the absence of spark and fuel. Furthermore, the engine speed decreases at an increased rate in response to the higher exhaust back pressure of the engine.

[0035] At time T2, the engine speed for line 402 of the engine speed control reaches zero, at which point the turbine blade state is adjusted to increase the turbine blade opening amount. Opening the turbine blades in response to the engine speed reaching zero reduces the exhaust backpressure as the engine stops, allowing exhaust gas to flow more easily from the engine cylinders. This, in turn, reduces exhaust residue in the engine cylinders, thus improving engine restart. The engine stop / start command remains at a lower level, indicating that the engine should remain in a stopped state (e.g., a non-rotating state).

[0036] At time T3, engine speed reaches zero when an engine is operated in accordance with prior art methods. Time T3 occurs later than time T2 because there is less engine pumping work when the engine is stopped in accordance with prior art methods, which include simply terminating fuel flow and spark to the engine.

[0037] At time T4, an engine restart request is generated, as indicated by the engine stop / start command transitioning from a lower level to a higher level. The engine stop / start command transitions in response to a driver releasing a vehicle brake pedal. The engine is cranked and started by supplying spark and fuel to the engine. The turbine blade state is adjusted to a less open state, which increases exhaust flow resistance within the engine exhaust system, in response to the engine stop / start command transitioning to an engine start / run state. If the engine is connected to a torque converter, the torque converter transfers less torque to the vehicle wheels when the engine speed is lower.

[0038] Between time T4 and time T5, the engine speed increases, with exhaust backpressure increasing with increasing engine speed. Further, the turbine blade state is adjusted in response to the actual engine speed. In one example, the turbine blade state is adjusted in response to a difference between a desired engine speed and an actual engine speed. The engine stop / start command remains at a higher level, indicating that the engine has been started. The engine speed in accordance with the method of the Fig. 8 and Fig. 9 is smaller than the engine speed of the prior art methods. Furthermore, the exhaust back pressure of the engine is in accordance with the method according to the Fig. 8 and Fig. 9 is greater than the exhaust back pressure of the engine of the prior art methods. Consequently, the higher exhaust back pressure of the method in accordance with the Fig. 8 and Fig. 9 the engine speed during engine start-up so that the torque transmitted to the vehicle wheels is reduced when the vehicle is in gear.

[0039] At time T5 and continuing until time T6, the engine first reaches a stabilized idling state, at which point the turbine blade state is adjusted in response to the engine speed and the requested engine torque. In other words, the engine pumping work is reduced while a set quantity of engine air is supplied to meet the engine torque requirement.

[0040] At time T6, the engine start / stop request transitions to a lower state to initiate automatic engine stopping in response to a driver applying a brake, vehicle speed reaching zero, and the absence of accelerator pedal depression. The turbine vane state is adjusted to a more closed position in response to the engine start / stop request transitioning to a lower state, with exhaust backpressure increasing in response to the turbine vanes moving to a more closed position. Engine speed also begins to decrease as spark and fuel supply cease.

[0041] At time T7, the engine start / stop request transitions from a lower state to a higher state to indicate that the driver has changed their intention (COM) and wishes the engine to continue running and rotating. The engine stop / start request transitions in response to a driver releasing the brake pedal. The turbine blade state is adjusted to increase the blade opening amount in response to the engine stop / start request transitioning to the higher level. The engine exhaust backpressure decreases in response to the increase in the turbine blade opening amount. The engine speed also begins to increase as spark and fuel flow to the engine resume.

[0042] In this way, the turbine blade position can be adjusted in response to the requirements for stopping and starting the engine. Furthermore, the turbine blade positions can be adjusted if a driver changes their intention after the engine has begun to stop and before the engine speed reaches zero.

[0043] In Fig. 5 shows another simulated engine operating sequence. The operating sequence can be achieved by executing the instructions of the method according to the Fig. 8 and Fig. 9 in the controller 12 of the Fig. 1-3 described system. The vertical markings T 10 -T 17 represent points of particular interest during the process. The graphical representations according to Fig. 5, which have the same names and reference symbols indicating the traces as the graphic representations according to Fig. 4 possess, are like in Fig. 4 is described, and they function as described in Fig. 4. Therefore, for the sake of brevity, only the differences in Fig. 5 described.

[0044] The fifth graphic representation from the top after Fig. Figure 5 shows the applied turbine shaft torque from a device such as an electric motor as shown in Fig. 3. In particular, the applied turbine shaft torque is a torque applied by an electric machine contained within the turbine shaft of a turbocharger. A positive shaft torque applied by the electric machine acts to accelerate the turbine shaft, while a negative torque applied by the electric machine acts to limit the movement of the turbine shaft. The electric machine acts like a motor when a positive torque is applied to the turbine shaft. The electric machine acts as a generator / alternator when a negative torque is applied to the turbine shaft. The applied negative turbine shaft torque increases in the direction of the downward-pointing Y-axis arrow. The applied positive turbine shaft torque increases in the direction of the upward-pointing Y-axis arrow.An applied turbine shaft torque at the X-axis level is an applied turbine shaft torque of zero.

[0045] At time T 10The engine is operating at a medium level of engine speed and the engine exhaust backpressure is at a medium level of engine exhaust backpressure. The turbocharger turbine blade state is at a medium level, indicating that the turbine blades are partially open. The engine stop / start command is at a high level, indicating that the engine is operating and is not requested to stop rotating. The applied turbine shaft torque is negative, indicating that the electric machine is acting as a generator / alternator because the desired engine torque decreases in response to a driver torque request. The generator / alternator can supply electrical power to an electrical energy storage device when it supplies negative torque to the turbine shaft.

[0046] At time T 11A power machine stop request is indicated by the state of the power machine stop / start command transitioning from a higher level to a lower level. The power machine stop / start request can be generated when a set of conditions for automatically stopping a power machine is met, without an operator directly requesting a stop via a dedicated input with a single function of stopping and / or halting a power machine (e.g., an ignition switch). In this example, the power machine stop request is generated in response to a vehicle speed reaching zero, a driver depressing the brake pedal, and an accelerator pedal not being depressed.

[0047] The engine is stopped by halting the fuel flow and spark to the engine in response to an engine stop / start request that transitions to a lower level. The turbine blade condition is adjusted to an increasingly closed state in response to an engine stop / start request that transitions to the lower level. In one example, the turbine blades are adjusted to an increasingly closed state after a cylinder has drawn in air for a final combustion event before the engine stops. In other examples, the adjustable turbine blades are set to increase the engine's exhaust backpressure by less than a threshold amount before a final cylinder, which burns an air-fuel mixture before the engine stops, draws in a significant amount of air.In this way, the last combustion event before the engine stops is not affected by adjusting the turbocharger blade position.

[0048] The applied turbine shaft torque is increased in the negative direction, indicating that it becomes increasingly difficult to turn the turbine shaft in response to the engine stop / start command transitioning to the lower level. Consequently, a higher exhaust pressure is required to turn the turbine shaft when a higher negative torque is applied to it.

[0049] The exhaust backpressure of the engine briefly increases in response to the turbine blade condition being adjusted to a more closed position and in response to the increased applied negative turbine shaft torque. However, the exhaust backpressure of the engine decreases as the engine speed decreases. It should also be noted that the exhaust backpressure reaches a higher level than during similar conditions observed in Fig. 4, where no electric machine is present. In addition, the engine exhaust backpressure of line 408 is greater than the engine exhaust backpressure of line 410. By increasing the engine exhaust backpressure, the engine pumping work increases, thereby removing more kinetic energy from the rotating engine so that the engine stops more quickly, as indicated by the engine speed line 402 decreasing more quickly than the engine speed line 404.

[0050] Between time T 11 and time T 12 The engine speed decreases in response to the lack of spark and fuel. Furthermore, the engine speed decreases at an increased rate in response to the higher exhaust backpressure of the engine.

[0051] At time T 12The engine speed for line 402 of the engine speed command reaches zero, at which point the turbine blade condition is adjusted to increase the turbine blade opening amount. By opening the turbine blades in response to the engine speed reaching zero, the exhaust backpressure is reduced as the engine stops, allowing the exhaust gas to flow more easily from the engine cylinders. This, in turn, reduces exhaust residue in the engine cylinders, thus improving engine restart. Furthermore, the applied negative turbine shaft torque also decreases to zero to allow the turbine to rotate. The engine stop / start command remains at a lower level, indicating that the engine should remain in a stopped state (e.g., a non-rotating state).

[0052] At time T 13When an engine is operated in accordance with prior art methods, the engine speed reaches zero. The applied turbine shaft torque remains at zero.

[0053] At time T 14A power engine restart request is generated, as indicated by the power engine stop / start command, which transitions from a lower level to a higher level. The power engine stop / start command transitions in response to a driver releasing a vehicle's brake pedal. The power engine is disengaged and started by supplying spark and fuel. The turbine blade state is adjusted to a less open state, increasing the exhaust flow resistance within the power engine's exhaust system in response to the power engine stop / start command transitioning to a power engine start / run state. The applied negative turbine shaft torque also increases to reduce turbine movement during the power engine start and ramp-up (e.g.,a period of time from when the engine speed is zero until the engine speed is at an idle speed or another predetermined speed).

[0054] Between time T 14 and time T 15The engine speed increases, and the exhaust backpressure also increases with increasing engine speed. Furthermore, the turbine blade condition is adjusted in response to the actual engine speed, as is the applied negative turbine shaft torque. In one example, the turbine blade condition and the applied negative turbine shaft torque are adjusted in response to a difference between a target engine speed and an actual engine speed. The engine stop / start command remains at a higher level, indicating that the engine has been started. The engine speed is adjusted in accordance with the procedure described below. Fig. 8 and Fig. 9 is smaller than the engine speed of the prior art methods. Furthermore, the exhaust back pressure of the engine is in accordance with the method according to the Fig. 8 and Fig. 9 is greater than the exhaust back pressure of the engine of the prior art methods. Consequently, the higher exhaust back pressure of the method in accordance with the Fig. 8 and Fig. 9 the engine speed during engine start-up so that the torque transmitted to the vehicle wheels is reduced when the vehicle is in gear.

[0055] At time T 15 and further until time T 16 The engine first reaches a stabilized idle state, at which point the turbine blade position is adjusted in response to the engine speed and the requested engine torque. The applied turbine shaft torque also changes from negative to positive to improve the air pressure supplied by the engine's compressor. Just before time T 16the applied turbine shaft torque turns negative, providing electrical energy to an electrical energy storage device in response to a driver reducing an engine torque request.

[0056] At time T 16The engine start / stop request transitions to a lower state to initiate automatic stopping of the engine in response to a driver applying a brake, vehicle speed reaching zero, and the absence of accelerator pedal depression. In response to the engine start / stop request transitioning to a lower state, the turbine state is adjusted to a more closed position and the applied negative turbine shaft torque is increased, with exhaust backpressure increasing in response to the turbine blades moving to a more closed position and the applied negative turbine shaft torque increasing. Engine speed also begins to decrease as the supply of spark and fuel ceases.

[0057] At time T 17The engine start / stop request transitions from a lower to a higher state to indicate that the driver has changed their intention (COM) and wishes the engine to continue operating and rotating. The engine stop / start request transitions in response to a driver releasing the brake pedal, which is interpreted as a COM. The turbine blade state is adjusted to increase the blade opening amount in response to the engine stop / start request transitioning to the higher level, with the applied turbine shaft torque switching from negative to positive. The engine exhaust backpressure decreases in response to the increase in the turbine blade opening amount and the change in applied turbine shaft torque.The engine speed also begins to increase, with the sparks and fuel flow being resumed to the engine.

[0058] In this way, the turbine blade position and the applied turbine shaft torque can be adjusted in response to the requirements for stopping and starting the engine. Furthermore, the turbine blade positions and the applied turbine shaft torque can be adjusted if a driver changes their intention after the engine has begun to stop and before the engine speed reaches zero.

[0059] In Fig. Figure 6 shows a block diagram of an example system containing a turbocharger with adjustable turbine blades. The block diagram applies to the system described in the Fig. 1-3 system shown and for the one in the Fig. 8 and Fig. 9 methods shown.

[0060] The engine model 604 gives an engine speed as a function f2 of the exhaust back pressure P B the power engine, the pressure P f of the intake manifold, the spark S, and other variables that include, but are not limited to, the engine temperature and air temperature. The intake manifold pressure model 610 estimates the intake manifold pressure P. f as a function f1 of the engine speed W c , of the air inlet pressure P in , the throttle valve position u th and other variables that include, but are not limited to, ambient temperature and ambient pressure. The intake manifold pressure model 610 outputs the intake manifold pressure.

[0061] The spark and throttle controller 606, in response to engine speed and other variables such as engine target torque, outputs spark and throttle commands to engine model 604 and intake manifold pressure model 610. The turbocharger / supercharger model 608, in response to a turbocharger blade position command 650 and other variables such as, but not limited to, the supercharger pressure ratio, outputs a supercharger speed to the intake manifold pressure model 610. The turbocharger / supercharger model 608 also outputs an engine back pressure value to engine model 604.

[0062] The turbocharger controller 602 outputs a turbocharger blade position command 650 in response to, but not limited to, an engine speed and other variables, such as the engine speed and the status of the engine stop / start command. The turbocharger controller 602 can operate as described in the procedure below. Fig. 8 and Fig. 9 is described.

[0063] In Fig. Figure 7 shows a block diagram of an alternative example system. The block diagram according to Fig. 7 contains elements that have the same reference symbols as the elements in Fig. possess 6. The elements according to Fig. 7, which have the same reference symbols as those in Fig. The ones shown in 6 are the same and work in the same way as in Fig. Section 6 is described. Therefore, for the sake of brevity, the description of the same elements has been omitted. The elements according to Fig. 7, which differ from those in Fig. The 6 described elements are distinguished and described.

[0064] The turbocharger model 708 includes representations of an electric machine (e.g., G3) for applying positive or negative turbine shaft torque. The turbocharger model 708 outputs a current estimate to the energy storage device model 702. The turbocharger controller 702 includes outputs for the blade position command 650 and the command 710 for the electric device. Consequently, the by Fig. 7 described system settings for an electric machine that is electrically and / or mechanically connected to a turbocharger.

[0065] In the Fig. 8 and Fig. Figure 9 now shows an example procedure for operating a power machine. The procedure according to the Fig. 8 and Fig. 9 can be used as non-volatile executable instructions in controller 12 after Fig. 1 be stored. The procedure according to the Fig. 8 and Fig. 9 can also be used in the Fig. 4 and Fig. Provide the 5 shown processes.

[0066] In 802, procedure 800 determines the vehicle's operating conditions. The vehicle's operating conditions may include, but are not limited to, the engine speed, engine load, engine set torque, brake pedal position, accelerator pedal position, vehicle speed, turbine blade position, and turbine shaft torque application device state. Procedure 800 proceeds to 803 after the operating conditions have been determined.

[0067] In procedure 803, procedure 800 assesses whether or not an engine stop or engine start request is generated. An engine stop or engine start request can be automatically generated by a controller in response to vehicle conditions other than dedicated driver input that has the single purpose of starting and / or stopping the engine. For example, an engine stop request can be generated when the engine speed is idle, the vehicle speed is zero, a vehicle brake is applied, and the accelerator pedal is not pressed. An engine start request can be generated when the engine speed is zero and the brake pedal is not applied.A manual stopping or starting of the power engine may be requested by a driver who activates a device that has a single function of starting and / or stopping a power engine. If procedure 800 determines that a stopping or starting of the power engine is requested, the answer is yes and procedure 800 proceeds to 804. Otherwise, the answer is no and procedure 800 proceeds to 825.

[0068] At 804, method 800 judges whether or not an electrically assisted turbine is provided with the engine. In one example, a bit may be set in memory to identify whether or not an electrically assisted turbine is present. If method 800 judges that an electrically assisted turbine is present, the answer is yes, and method 800 proceeds to 805. Otherwise, the answer is no, and method 800 proceeds to 815.

[0069] In Fig. Procedure 800 at 805 assesses whether the engine will be started. For example, it can be determined that the engine will be started if its rotational speed is less than a threshold speed and a start request is present. If Procedure 800 assesses that the engine will be started, the answer is yes, and Procedure 800 proceeds to 810. Otherwise, the answer is no, and Procedure 800 proceeds to 806. Consequently, the engine will be stopped when Procedure 800 proceeds to 806.

[0070] In 806, method 800 increases the degree to which the turbocharger turbine blades are closed by applying an increasing amount of negative torque to the turbocharger turbine shaft. The turbocharger turbine blades can be closed by adjusting the position of an electric actuator. The negative torque applied to the turbocharger turbine shaft can be increased by increasing a field current supplied to the generator / alternator. In one example, the position of the turbine blades and the negative torque applied by the generator / alternator can be adjusted in response to the engine speed during engine stoppage. For example,If the actual engine speed during engine shutdown is greater than the engine's set speed after spark and fuel have been deactivated, the turbine blades close further and additional negative torque is applied to the turbocharger turbine shaft by the generator / alternator. If the actual engine speed during engine shutdown is less than the engine's set speed after spark and fuel have been deactivated, the turbine blades open further and less negative torque is applied to the turbocharger turbine shaft by the generator / alternator.

[0071] In one example, adjustments to the turbine blades and generator / alternator are performed after a last cylinder combusting an air-fuel mixture after the engine stop request has drawn its last amount of air participating in combustion after the engine stop request. In another example, the position of the adjustable turbine blades and the negative torque of the generator / alternator are adjusted to increase engine exhaust backpressure by less than a threshold amount at a time before a last cylinder combusting an air-fuel mixture before engine stop draws an amount of air participating in combustion.Consequently, by adjusting the turbine blade position and the field current supplied to the generator / alternator, it may be possible to adjust the exhaust backpressure of the engine and the engine speed during engine shutdown. Method 800 continues to 807 after the turbocharger blade position and the negative torque have been applied to the turbocharger turbine shaft.

[0072] In procedure 807, procedure 800 assesses whether a change of intent by the driver occurs after a request to stop the engine. A change of intent can be determined if, after a request to stop the engine and before the engine has stopped rotating, the driver releases the brake pedal or applies the accelerator pedal. If procedure 800 determines that a change of intent has occurred, the answer is yes, and procedure 800 proceeds to 809. Otherwise, the answer is no, and procedure 800 proceeds to 808.

[0073] At 808, method 800 judges whether or not the engine has stopped rotating. It may be judged that the engine has stopped rotating based on a signal from a crankshaft position sensor. If method 800 judges that the engine has stopped rotating, the answer is yes, and method 800 proceeds to 809. Otherwise, the answer is no, and method 800 returns to 807.

[0074] At 809, method 800 increases a turbine blade opening amount while decreasing an amount of negative torque applied to the turbocharger turbine shaft. The negative torque applied to the turbocharger turbine shaft may be reduced by reducing the field current supplied to the generator / alternator. By increasing the opening amount of the turbocharger turbine blades and the negative torque applied to the turbocharger turbine shaft, the exhaust gases upstream of the turbine may be vented to the downstream side of the turbine, thus reducing the amount of exhaust gas in the engine cylinders. Reducing the amount of exhaust gas in the engine cylinders may improve engine starting because combustion may be more stable in the cylinder less diluted with exhaust gas.Procedure 800 continues to 825 after the turbine blades and the generator / three-phase generator have been adjusted.

[0075] In procedure 810, procedure 800 assesses whether a power machine torque request is greater than a power machine threshold torque request. In one example, the power machine torque request is provided by an accelerator pedal position, which is converted into a power machine torque request via an accelerator pedal position transfer function. In other examples, the power machine torque request can be provided by a controller. If procedure 800 assesses that the power machine torque request is greater than a threshold torque request, the answer is yes, and procedure 800 proceeds to 811. Otherwise, the answer is no, and procedure 800 proceeds to 812.

[0076] In 811, method 800 adjusts the turbine blade condition of the turbocharger and the torque applied to the turbine shaft in response to the engine's torque demand. In one example, the turbine blade opening is increased, and the applied turbine shaft torque is switched from negative to positive. Increasing the turbine blade opening reduces the force exerted on the turbine by the exhaust gases and decreases the engine's exhaust backpressure. Switching the applied turbine shaft torque from negative to positive by changing the electrical device from a generator / alternator to a motor brings the compressor up to operating speed more quickly, thus increasing the airflow to the engine.The change in turbine blade position and applied turbine shaft torque may be adjusted proportionally to the engine torque request. Method 800 proceeds to 812 after the turbine blades and applied turbine shaft torque have been adjusted.

[0077] In 812, procedure 800 increases the turbine blade closing amount and the applied negative turbine torque to increase the engine's exhaust backpressure. In one example, the turbine blade position and negative torque are commanded to a position that changes with atmospheric pressure. The turbine blade closing amount, for example, is decreased as atmospheric pressure increases. Consequently, the settings in 811 and 812 can be combined to adjust the turbine blades and the applied turbine shaft torque in a manner that accommodates changes in the engine's torque requirement and exhaust backpressure during engine start-up. Procedure 800 proceeds to 813 after the turbine blade and applied turbine shaft torque settings have been executed.

[0078] In 813, method 800 adjusts the turbine blade position and the applied turbine shaft torque in response to the engine speed during engine start-up. For example, if the engine speed is greater than a target engine speed, the turbine blade closing amount is increased, and the applied negative turbine shaft torque is increased. Increasing the turbine blade closing amount and the applied negative torque increases the engine's exhaust backpressure to increase the engine's internal EGR (e.g., to expel the residues remaining in the cylinder after the exhaust valve closes during a cylinder cycle). The increased internal EGR can decrease engine torque because less oxygen may be available to participate in combustion within each cylinder.Similarly, if the engine speed is less than the desired engine speed, the turbine blade opening amount is increased and the applied negative turbine torque is decreased to reduce engine exhaust backpressure. The desired engine speed during startup may be stored as an engine speed trajectory in controller memory. Method 800 proceeds to 814 after the turbine blade position and applied turbine shaft torque are adjusted in response to the engine speed.

[0079] At 814, method 800 judges whether or not the engine has been started and whether selected conditions are met. Method 800 may judge that the engine has been started if the engine speed is greater than an engine threshold number. Additionally, other conditions, such as the time since the engine stopped being greater than a threshold time period and the engine speed being greater than a threshold speed, may also need to be met to answer yes before proceeding to 825. If the engine has been started and selected operating conditions are met, the answer is yes and method 800 proceeds to 825. Otherwise, the answer is no and method 800 returns to 810.

[0080] Back in Fig. 8, at 815, method 800 judges whether the engine is being started. The engine may be determined to be started if the engine speed is less than a threshold speed and if an engine start request is present. If method 800 judges that the engine is being started, the answer is yes, and method 800 proceeds to 820. Otherwise, the answer is no, and method 800 proceeds to 816. Consequently, the engine is stopped when method 800 proceeds to 816.

[0081] At 816, method 800 increases the amount the turbocharger turbine blades are closed. The turbocharger turbine blades may be closed by adjusting a position of an electric actuator. In one example, the position of the turbine blades may be adjusted in response to engine speed during engine stopping.

[0082] In one example, the turbine blade adjustments are made after the last cylinder, burning an air-fuel mixture following the engine stop request, has drawn in its final amount of air participating in the combustion. In another example, the position of the adjustable turbine blades is set before the last cylinder, burning an air-fuel mixture prior to engine stop, draws in its final amount of air participating in the combustion, in order to increase the engine's exhaust backpressure by less than a threshold value. Consequently, by adjusting the turbine blade position, it may be possible to control the engine's exhaust backpressure and engine speed during engine stop.Method 800 proceeds to 817 after the turbocharger blade position and negative torque are applied to the turbocharger turbine shaft.

[0083] In procedure 817, procedure 800 assesses whether or not a change of intent by the driver occurs after a request to stop the engine. A change of intent can be determined by whether, after a request to stop the engine and before the engine has stopped rotating, the driver releases the brake pedal or applies the accelerator pedal. If procedure 800 determines that a change of intent has occurred, the answer is yes, and procedure 800 proceeds to 819. Otherwise, the answer is no, and procedure 800 proceeds to 818.

[0084] At step 818, procedure 800 assesses whether the rotation of the engine has stopped or not. It can assess whether the rotation of the engine has stopped based on a signal from a crankshaft position sensor. If procedure 800 assesses that the rotation of the engine has stopped, the answer is yes, and procedure 800 proceeds to 819. Otherwise, the answer is no, and procedure 800 returns to 817.

[0085] In process 800, procedure 819 increases the turbine blade opening. By increasing the turbine blade opening of the turbocharger, the exhaust gases can be discharged upstream of the turbine to the downstream side of the turbine, thus reducing the amount of exhaust gas in the engine cylinders. Reducing the amount of exhaust gas in the engine cylinders can improve engine starting because combustion can be more stable in a cylinder that is less diluted with exhaust gas. Procedure 800 continues to 825 after the turbine blades have been adjusted.

[0086] At 820, method 800 judges whether an engine torque request is greater than a threshold engine torque request. If method 800 judges that the engine torque request is greater than a threshold torque request, the answer is yes, and method 800 proceeds to 821. Otherwise, the answer is no, and method 800 proceeds to 822.

[0087] At 821, method 800 adjusts the turbine blade state of the turbocharger in response to an engine torque demand. In one example, the turbine blade opening amount is increased. Increasing the turbine blade opening amount reduces the force exerted on the turbine by the exhaust gases and reduces the engine exhaust backpressure. The change in turbine blade position may be adjusted proportional to the engine torque demand. Method 800 proceeds to 822 after the turbine blades have been adjusted.

[0088] In 812, procedure 800 increases the turbine blade closing amount and the applied negative turbine torque to increase the engine's exhaust backpressure. In one example, the turbine blade position is commanded to a position that varies with atmospheric pressure. The turbine blade closing amount is decreased, for example, as the atmospheric pressure increases. Consequently, the settings in 821 and 822 can be combined to adjust the turbine blades in a manner that accommodates changes in the engine's torque requirement and exhaust backpressure during engine start-up. Procedure 800 proceeds to 823 after the turbine blade settings have been executed.

[0089] In process 800, described in 823, the turbine blade position is adjusted in response to the engine speed during engine start-up. For example, if the engine speed is greater than the engine setpoint speed, the turbine blade closing amount is increased. Increasing the turbine blade closing amount increases the engine's exhaust backpressure to increase the engine's internal EGR. The increased internal EGR can reduce engine torque because less oxygen is available to participate in combustion in the individual cylinders. Similarly, if the engine speed is less than the engine setpoint speed, the turbine blade opening amount is increased to reduce the engine's exhaust backpressure. Process 800 proceeds to 824 after the turbine blade position has been adjusted in response to the engine speed.

[0090] At 824, procedure 800 assesses whether the engine has been started and whether selected conditions are met. Procedure 800 can assess that the engine has been started if the engine speed is greater than an engine threshold speed. Furthermore, other conditions, such as the time since the engine was stopped being greater than a threshold period and the engine speed being greater than a threshold speed, may need to be met to answer "yes" before proceeding to 825. If the engine has been started and the selected operating conditions are met, the answer is "yes," and procedure 800 proceeds to 825. Otherwise, the answer is "no," and procedure 800 returns to 820.

[0091] At step 825, procedure 800 assesses whether an electrically assisted turbine is present. In one example, a bit in memory can be set to identify whether an electrically assisted turbine is present. If procedure 800 assesses that an electrically assisted turbine is present, the answer is yes, and procedure 800 proceeds to step 826. Otherwise, the answer is no, and procedure 800 proceeds to step 827.

[0092] In 826, method 800 adjusts the turbine blade state of the turbocharger and an electrical device in response to operating conditions. In one example, the turbine blade state is adjusted in response to a target engine torque, exhaust system back pressure, and a compressor pressure ratio. For example, when the engine speed is low and the target torque is high, the turbine blades are adjusted to a more closed position. When the engine speed is at a medium level and the engine torque demand is at a medium level, the turbine blades are adjusted to a more open position.

[0093] The electrical device, which applies torque to the turbine shaft, can operate to provide positive torque to the turbine shaft when a command to increase the engine torque is present and when the engine speed is below a threshold speed. Conversely, the electrical device can operate to provide negative torque to the turbine shaft and recharge an energy storage device when a command to decrease the engine torque is present and when the engine speed is below a threshold speed. Method 800 proceeds to the output after the turbine blades and the electrical device have been set.

[0094] In procedure 800, process 826 adjusts the turbine blade condition of the turbocharger in response to the operating conditions. In one example, the turbine blade condition is adjusted in response to a target engine torque, exhaust system back pressure, and a compressor pressure ratio. Process 800 proceeds to the output after the turbine blade area has been set.

[0095] Consequently, the procedure according to the Fig. 8 and Fig. 9 provides an engine control method comprising: adjusting a vane position of a turbocharger in response to requests to stop and start the engine to increase engine exhaust backpressure; and adjusting the vane position of the turbocharger to decrease engine exhaust backpressure after adjusting the vane position of the turbocharger to increase engine exhaust backpressure during engine stopping. The engine control method includes: stopping the engine includes rotating the engine during engine stopping. The engine control method further includes adjusting the vane position in response to engine speed during engine start-up.

[0096] In another example, the engine control method further comprises increasing a negative torque of an electric machine in communication with the turbocharger during engine stopping and engine starting. The engine control method further comprises adjusting the vane position to at least partially open the turbine vanes of the turbocharger during a driver intent change condition during engine stopping. The engine control method further comprises adjusting the vane position during engine starting in response to an engine torque request during engine startup.

[0097] As an average expert in the field would recognize, this can occur in the Fig. 8 and Fig. The procedures described in section 9 represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. As such, the illustrated steps or functions may be executed in the illustrated order, executed in parallel, or, in some cases, omitted. Likewise, the order of processing is not necessarily required to achieve the tasks, features, and benefits described herein, but is provided for ease of illustration and description. Although not explicitly illustrated, an average professional in the field will recognize that one or more of the illustrated steps or functions may be executed repeatedly, depending on the particular strategy employed.

[0098] This concludes the description. Those skilled in the art would recognize many changes and modifications upon reading the description, without deviating from the inventive concept and the scope of the description. The present description could be advantageously used, for example, by single-cylinder, I2, I3, I4, I5, V6, V8, V10, V12, and V16 engines operating on natural gas, gasoline, diesel, or alternative fuel configurations. KEY: Fig. 8: START BEGINNING OF Fig. 9 802 DETERMINE THE OPERATING CONDITIONS 803 START OR STOP THE POWER MACHINE? NO NO YES YES 804 ELECTRICALLY SUPPORTED TURBINE? 815 STARTING THE POWER MACHINE? 816 Enlarge after air intake into the last burning cylinder to close the turbine blades in order to increase exhaust back pressure 817 DOES THE OPERATOR CHANGE THEIR INTENTION? 818 HAS THE POWER MACHINE STOPPED? 819 Increase the opening of the turbine blades to reduce exhaust back pressure 820 IS THE ENGINE TORQUE REQUIREMENT GREATER THAN A THRESHOLD? 821 SET TURBOCHARGER BLADE STATE IN RESPONSE TO ENGINE SPEED REQUEST 822 Increase turbine blade closing to increase exhaust back pressure 823 Adjust turbine blade position during start-up in response to engine speed 824 HAS THE ENGINE BEEN STARTED AND ARE THE STARTING CONDITIONS MET? 825 ELECTRICALLY SUPPORTED TURBINE? 826 ADJUST TURBOCHARGER BLADE STATE AND ENGINE IN RESPONSE TO OPERATING CONDITIONS 827 ADJUST TURBOCHARGER BLADE STATE IN RESPONSE TO OPERATING CONDITIONS Fig. 9: 805 STARTING THE POWER MACHINE? NO NO 806 After air intake into the last burning cylinder, increase the closing of the turbine blades and the turbine shaft torque applied to increase the exhaust back pressure. 807 DOES THE OPERATOR CHANGE THEIR INTENTION? 808 HAS THE POWER MACHINE STOPPED? 809 Increase the opening of the turbine blades and the applied turbine shaft torque to reduce exhaust back pressure 810 IS THE ENGINE TORQUE REQUIREMENT GREATER THAN A THRESHOLD? 811 Adjust the turbocharger blade condition and applied turbine shaft torque in response to the engine speed request 812 Increase turbine blade closing and applied turbine shaft torque to increase exhaust back pressure 813 POSITION IN RESPONSE TO THE POWER ENGINE SPEED, TURBINE BLADE POSITION AND THE APPLIED TURBINE SHAFT TORQUE DURING START-UP 814 HAS THE POWER MACHINE BEEN STARTED AND ARE THE STARTING CONDITIONS MET?

Claims

[1] Power machine system comprising: a power machine (10); a turbocharger coupled to the engine (10), the turbocharger including adjustable turbine blades (230); and a controller (12) configured to adjust a turbine blade position to an increasingly closed position in response to a request to stop the engine (10) to increase an exhaust backpressure of the engine (10), characterized by , that a time of the request to stop the engine (10) and a time of setting the turbine blade position to an increasingly closed position equal to a first time (T1, T 11 ) and the controller (12) is further configured to control the setting to an increasingly closed position such that the exhaust back pressure of the engine (10) increases briefly. [2] The engine system of claim 1, wherein the controller (12) is further configured to adjust the turbine blade position such that the exhaust backpressure of the engine (10) increases by less than a threshold amount at a second time before a last cylinder combusting an air-fuel mixture prior to stopping the engine (10) draws in an amount of air that participates in combustion after the request to stop the engine (10). [3] The engine system of claim 1, wherein the controller (12) is further configured to adjust the turbine blade position to an increasingly closed position at a third time after a last cylinder combusting an air-fuel mixture before stopping the engine (10) draws in an amount of air. [4] The engine system of claim 1, wherein the controller (12) is further configured to at least partially open the adjustable turbine blades (230) after the exhaust back pressure of the engine (10) has been increased. [5] The engine system of claim 4, wherein the controller (12) is further configured to cause the at least partial opening of the adjustable turbine blades (230) to occur in response to a condition of changing operator intent. [6] The engine system of claim 4, wherein the controller (12) is further configured to relate the at least partial opening of the adjustable turbine blades (230) to a period of stopping the engine (10). [7] The engine system of claim 1, further comprising a turbocharger turbine torque adjuster (300), and wherein the controller (12) is further configured to, at the first time (T 11 ) to increase a negative torque applied to the turbocharger by the turbocharger turbine torque adjusting device (300). [8] The engine system of claim 4, wherein the controller (12) is further configured to control at least partial opening of the adjustable turbine blades (230) in response to an engine speed determined at a fourth time (T2, T 12 ) reaches zero, whereby the fourth time point (T2, T 12 ) after the first time point (T1, T 11 ) lies. [9] Engine system according to the preceding claim, wherein the controller (12) is further configured to, at a fifth time (T4, T 14) to generate an engine restart request and adjust the turbine blade position to a less open state, wherein the fifth time point (T4, T 14 ) after the fourth time point (T2, T 12 ) lies. [10] The engine system of claim 1, wherein the controller (12) is further configured to reduce an amount of oxygen delivered to a converter (70).

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