Wastegate control method for engine noise emissions

Abstract

Turbocharger control method for a vehicle, comprising: generating a trigger signal; in response to the generation of the trigger signal, setting a target opening of a turbocharger wastegate to a predetermined opening, wherein the predetermined opening is greater than the zero percent opening of the turbocharger wastegate; and actuating the turbocharger wastegate based on the desired opening of the turbocharger wastegate; characterized in that the trigger signal is generated when an accelerator pedal is depressed while a transmission of the vehicle is in a (i) park or a (ii) neutral position.

Description

REGIONThe present disclosure relates to internal combustion engines, and more particularly to a method for controlling turbocharger wastegates for engine sound emission according to the preamble of claim 1, such as is substantially known from US 2013 / 0 098 032 A1.BACKGROUNDInternal combustion engines combust a fuel / air mixture in cylinders to move the pistons to generate the drive torque. In some types of engines, airflow into the engine may be regulated via a throttle. The throttle may adjust the throttle range, thereby increasing or decreasing airflow into the engine. As the throttle area is increased, the air supply to the engine also increases. A fuel control system adjusts the fuel injection amount to provide a desired fuel / air mixture to the cylinders and / or achieve a desired torque output. Generally, by increasing the amount of air and fuel provided to the cylinders, the torque output of the engine increases.Some engines may be equipped with one or more boosting devices, such as one or more turbochargers or a compressor. Boost devices pump air into the engine to increase the efficiency and / or maximum power output capability of the engine. Compressors are driven by the crankshaft while turbochargers are driven by exhaust flow through an exhaust system.SUMMARYA turbocharger control method of a vehicle having the features of claim 1 is proposed.In further features, if the trigger signal is not generated, the turbocharger control method further includes adjusting the target opening of the turbocharger wastegate based on the accelerator pedal position.In further features, if the trigger signal is not generated, the turbocharger control method further includes: decreasing the target opening of the turbocharger wastegate when a driver actuates the accelerator pedal away from a predefined accelerator pedal rest position; and increasing the target opening of the turbocharger wastegate when the driver releases the accelerator pedal toward the predefined accelerator pedal rest position.In further features, the predetermined opening is at least 30 percent opening of the turbocharger wastegate.In further features, the predetermined opening is less than 100 percent opening of the turbocharger wastegate.In further features, generating the trigger signal includes generating the trigger signal when true: the transmission is in a forward (iii) gear and a reverse (iv) gear, respectively; a clutch pedal is operated away from a predetermined clutch pedal rest position; and a vehicle speed is less than a predetermined speed. The predetermined speed may be greater than zero.In further features, the turbocharger control method further includes not generating the trigger signal when the clutch pedal moves toward the predefined clutch pedal rest position.In further features, the turbocharger control method further includes not generating the trigger signal when the clutch pedal moves to the predefined clutch pedal rest position.In further functions, at least each of the first and second predetermined accelerations has a negative value.BRIEF DESCRIPTION OF THE DRAWINGSThe present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: FIG. 1 is a functional block diagram of an example powertrain system; FIG. 2 is a functional block diagram of an exemplary engine control system; and FIGS. 3-5 are flowcharts illustrating the example methods for controlling opening of a turbocharger wastegate to emit more engine noise.In the drawings, the same reference numerals are used for similar and / or identical elements.DETAILED DESCRIPTIONInternal combustion engines combust air and fuel in cylinders. Exhaust gas as a result of combustion in the cylinders flows through an exhaust system. Some engines include one or more turbochargers. Exhaust flow through the exhaust system drives a turbocharger turbine. The turbocharger turbine is mechanically coupled to a turbocharger compressor and the turbocharger turbine drives the turbocharger compressor. The turbocharger compressor pumps air into the engine.A turbocharger wastegate controls exhaust flow (i) through the turbocharger turbine and through the (ii) bypass of the turbocharger turbine. Opening the turbocharger wastegate increases exhaust gas around the turbocharger turbine, thereby reducing turbocharger compressor output. Conversely, closing the turbocharger wastegate increases exhaust flow through the turbine of the turbocharger and increases the output of the turbocharger compressor. In technical terms, the boost pressure opening increases with respect to the working output of the turbine and the compressor is the consumer of this work.An engine control unit (ECM) of a vehicle controls engine actuators based on a requested desired torque. According to the present invention, the ECM controls the turbocharger wastegate opening to improve engine sound emission under certain circumstances.For example, the ECM may close the turbocharger wastegate from a fully or partially open position when a driver pressurizes an accelerator pedal of the vehicle including times when a transmission of the vehicle is in drive, park, reverse, or neutral. This may be done, for example, to prepare the turbocharger to increase the air flow into the engine.However, closing the turbocharger wastegate dampens the natural engine sound characteristic by pushing exhaust flow through the turbine of the turbocharger turbine. Therefore, when the driver pressurizes the accelerator pedal while the transmission is in park or neutral, the ECM maintains the turbocharger wastegate in the fully or partially open position or continues to open the turbocharger wastegate to the fully or partially open position. Maintaining the turbocharger wastegate open or further opening the turbocharger wastegate allows more of the natural engine noise to be emitted and heard when the driver pressurizes the accelerator pedal while the transmission is in park or neutral.In FIG. 1, a functional block diagram of an example vehicle system 100 is presented. The engine system 100 of a vehicle includes an engine 102 that burns an air / fuel mixture to generate torque based on driver inputs from a driver input module 104.Air is drawn into the engine 102 through an intake system 108. The intake system 108 may include an intake manifold 110 and a throttle 112. For example only, the throttle valve 112 may include a butterfly valve having a rotatable vane. An engine control unit (ECM) 114 controls a throttle actuator module 116 and the throttle actuator module 116 regulates opening of the throttle 112 to control airflow into the intake manifold 110.Air from the intake manifold 110 is drawn into the cylinders of the engine 102. Although the engine 102 includes multiple cylinders, a single representative cylinder 118 is shown for illustrative purposes. For example only, cylinder 102 may include 2, 3, 4, 5, 6, 8, 10, and / or 12 cylinders. The ECM 114 may instruct a cylinder actuator module 120 to selectively deactivate some of the cylinders in some circumstances, as discussed below, which may improve fuel economy.Engine 102 may operate using a four stroke cycle or other suitable engine cycle. The four strokes of a four stroke cycle, which will be described below, are referred to as the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. During each revolution of a crankshaft (not shown), two of the four strokes occur within cylinder 118. Thus, two revolutions of the crankshaft are required to allow the cylinder 118 to perform all four strokes. In four stroke engines, one engine cycle may correspond to two crankshaft revolutions.When cylinder 118 is activated, air is drawn from intake manifold 110 into cylinder 118 through intake valve 122 during the intake stroke. The ECM 114 controls a fuel actuator module 124 that regulates fuel injection to achieve a desired air-fuel ratio.Fuel may be injected into the intake manifold 110 at a central location or multiple locations, such as near the intake valve 122 of each cylinder. In various implementations (not shown), fuel may be injected directly into the cylinders or into mixing chambers / ports connected to the cylinders. The fuel actuator module 124 may stop injecting fuel into the deactivated cylinders.The injected fuel mixes with air and forms an air-fuel mixture within the cylinder 118. During the compression stroke, a piston (not shown) in cylinder 118 compresses the air-fuel mixture. The engine 102 may be a compression ignition engine, in which case the compression causes the ignition of the air-fuel mixture. Alternatively, the engine 102 may be a spark-ignition engine, in which case the spark actuator module 126 energizes a spark plug 128 in the cylinder 118 based on a signal from the ECM 114, thereby igniting the air-fuel mixture. Some types of engines, such as homogeneous-charge diesel engines (HCCI), may perform both compression and spark ignition. The timing of the spark may be specified relative to the time when the piston is at its top position, referred to as top dead center (TDC).The spark actuator module 126 may be controlled by a timing signal that determines how long before or after the TDC the spark is to be triggered. Because the piston position is directly related to crankshaft rotation, operation of the spark actuator module 126 may be synchronized with the position of the crankshaft. The spark actuator module 126 may deactivate provision of spark to deactivated cylinders or provide spark to deactivated cylinders.During the combustion stroke, the combustion of the air-fuel mixture drives the piston downward, thereby driving the crankshaft. The combustion stroke may be defined as the time elapsed between reaching the TDC of the piston and returning the piston to a lowermost position referred to as bottom dead center (BDC).During the exhaust stroke, the piston begins to move upward from the BDC and ejects the byproducts of combustion through an exhaust valve 130. The combustion waste products are exhausted from the vehicle via an exhaust system 134.Intake valve 122 may be controlled by intake camshaft 140, while exhaust valve 130 may be controlled by exhaust camshaft 142. In various applications, multiple intake camshafts (including intake camshaft 140) may control multiple intake valves (including intake valve 122) for cylinder 118, and / or may control the intake valves (including intake valve 122) of multiple cylinder banks (including cylinder 118). Similarly, multiple exhaust camshafts (including exhaust camshaft 142) may control multiple exhaust valves for cylinder 118 and / or may control exhaust valves (including exhaust valve 130) of multiple cylinder banks (including cylinder 118). Although camshaft-based valve actuation has been illustrated and discussed, camless valve actuators may be implemented. Although separate intake and exhaust camshafts are shown, a camshaft having cams for the intake and exhaust valves may be used.The cylinder actuator module 120 may deactivate the cylinder 118 by deactivating opening of the intake valve 122 and / or the exhaust valve 130. The time when the intake valve 122 is opened may be varied relative to the TDC of the piston by an intake cam phaser 148. The time when the exhaust valve 130 is opened may be varied relative to the TDC of the piston by an exhaust cam phaser 150. An adjusting actuator module 158 may control the intake cam phaser 148 and the exhaust cam phaser 150 based on signals from the ECM 114. In various applications, camshaft adjustment can be dispensed with. Variable valve lift (not shown) may also be controlled by the variable actuator module 158. In various other implementations, the intake valve 122 and / or the exhaust valve 130 may be controlled by actuators other than a camshaft, such as electro-mechanical actuators, electro-hydraulic actuators, electromagnetic actuators, etc.Engine system 100 includes one or more turbochargers that provide compressed air to intake manifold 110. For example, FIG. 1 illustrates a turbocharger including a turbine 160- 1 driven by exhaust gases flowing through the exhaust system 134. The turbocharger also includes a compressor 160- 2 that is driven by the turbocharger turbine 160- 1 and compresses air directed into the throttle 112. As discussed further below, engine system 100 may include more than one turbocharger, such as sequential or parallel turbochargers.Wastegate 162 controls exhaust flow through turbocharger turbine 160- 1 and its bypass. Wastegates may also be referred to as (turbocharger) turbine bypass valves. Wastegate 162 may direct the exhaust gases past turbine 160- 1, thereby reducing turbocharger generated boost pressure (the amount of intake air compression). The ECM 114 may control the turbocharger via a wastegate actuator module 164. Wastegate actuator module 164 may vary the boost of the turbocharger by controlling the opening of wastegate 162. In various implementations, multiple turbochargers may be controlled by wastegate actuator module 164. The turbocharger may have a variable geometry that may be controlled by a turbo actuator module (not shown).A radiator (e.g., a charge air cooler or intercooler) may dissipate a portion of the heat contained in the compressed air charge that may be generated when the air is compressed. Although shown separately for purposes of illustration, turbine 160- 1 and compressor 160- 2 may be mechanically coupled together with intake air positioned very close to hot exhaust gases. The compressed air charge may absorb heat from components of the exhaust system 134.The engine system 100 may include an exhaust gas recirculation (EGR) valve 170 that selectively recirculates exhaust gas to the intake manifold 110. The EGR valve 170 may be disposed upstream of the turbine 160- 1 of the turbocharger. The EGR valve 170 may be controlled by an EGR actuator module 172.Crankshaft position may be measured using a crankshaft position sensor 180. An engine speed may be determined based on the crankshaft position measured using the crankshaft position sensor 180. A temperature of the engine coolant may be measured using an engine coolant temperature sensor (ECT) 182. The ECT sensor 182 may be disposed within the engine 102 or at other locations where the coolant is circulated, such as at a heat exchanger (not shown).Pressure in intake manifold 110 may be measured using a manifold absolute pressure (MAP) sensor 184. In various applications, the engine negative pressure comprised of the difference between the ambient air pressure and the pressure in the intake manifold 110 may be measured. The mass flow rate of air flowing through the intake manifold 110 may be measured using an air flow mass (MAF) sensor 186. In various implementations, the MAF sensor 186 may be positioned in a housing that also includes the throttle valve 112.The position of the throttle 112 may be measured using one or more throttle position sensors (TPS) 190. A temperature of air drawn into the engine 102 may be measured using an intake air temperature sensor (IAT) 192. The engine system 100 may also include one or more other sensors 193. The other sensors 193 may include a clutch position sensor and / or one or more other suitable sensors. The ECM 114 may use signals from the sensors to make control decisions for the engine system 100.The other sensors 193 include an accelerator pedal position (APP) sensor, may include a clutch pedal position (CPP) sensor (e.g., in a manual transmission), and may include one or more other types of sensors. An APP sensor measures a position of an accelerator pedal within a passenger compartment of the vehicle. A CPP sensor measures a position of a clutch pedal within the passenger compartment of the vehicle. The other sensors 193 may also include one or more acceleration sensors that measure longitudinal acceleration of the vehicle.For example, the ECM 114 may communicate with a transmission control module 194 to coordinate operation of the engine with shifting gears in a transmission 195. For example, during a gear change, the ECM 114 may reduce engine torque. For example, the ECM 114 may communicate with a hybrid control module 196 to coordinate operation of the engine 102 and an electric motor 198. The electric motor 198 may also operate as a generator and serve to generate electrical energy for use in the vehicle's electrical system or for storage in a battery. Although only the electric motor 198 is illustrated and discussed, multiple electric motors may be implemented. In various applications, various functions of the ECM 114, the transmission control module 194, and the hybrid control module 196 may be incorporated into one or more modules.The transmission 195 may be, for example, an automatic transmission or a manual transmission. In manual transmissions, the driver actuates the clutch pedal and manually switches gears, for example via a manual shift lever. In automatic transmissions, the transmission control module 194 may control shift operations in response to driver input (e.g., commanded shift operations via contactors) and / or based on various operating parameters.In automatic transmissions, the transmission control module 194 controls the transmission 195 to a park(s)(m), reverse, neutral, forward, low (PRNDL) module 199 based on driver inputs. The PRNDL module 199 may indicate whether the driver has commanded the transmission 195 to operate in park, reverse, neutral, forward, low, or other transmission range. In manual transmissions, the transmission control module 194 may determine a currently engaged gear within the transmission 195 based on one or more transmission sensors within the transmission 195 and / or one or more manual lever position sensors within the vehicle cabin.Any system that affects an engine parameter may be referred to as an engine actuator. Each engine actuator has an associated actuator value. For example, the throttle actuator module 116 may be referred to as an engine actuator and the throttle opening range may be referred to as the actuator value. In the example of FIG. 1, the throttle actuator module 116 reaches the throttle opening range by adjusting an angle of the vane of the throttle 112.The spark actuator module 126 may also be referred to as an engine actuator, although the corresponding actuator value may be the degree of pre-ignition with respect to the TDC of the cylinder. Other engine actuators may include the cylinder actuator module 120, the fuel actuator module 124, the phaser actuator module 158, the boost actuator module 164, and the EGR actuator module 172. For these actuators, the actuator values may correspond to a cylinder activation / deactivation sequence, fueling rate, intake and exhaust cam pitch angles, wastegate desired openings, and EGR valve opening range, respectively. The ECM 114 may control the actuator values to cause the engine 102 to generate a requested engine output torque.Referring now to FIG. 2, a functional block diagram of an exemplary engine control system is shown. A torque request module 204 determines a torque request 208 for the engine 102 based on one or more driver inputs 212. The driver inputs 212 may include, for example, an accelerator pedal position, a brake pedal position, a cruise control input, and / or one or more other suitable driver inputs. For example, the torque request 208 may increase as the accelerator pedal position increases (relative to a predetermined resting accelerator pedal position such as zero), and vice versa. The torque request module 204 may additionally or alternatively determine the torque request 208 based on one or more torque requests, such as torque requests generated by the ECM 114 and / or torque requests received from other modules of the vehicle, such as the transmission controller 194, the hybrid control module 196, a body control module, etc.One or more engine actuators are controlled based on the torque request 208 and / or one or more other parameters. For example, a throttle control module 216 may determine a desired throttle opening 220 based on the torque request 208. For example, a throttle actuator module 116 may adjust the opening of the throttle 112 based on the desired throttle opening 220.A spark control module 224 determines a target spark timing 228 based on the torque request 208. The spark actuator module 126 generates a spark based on the desired spark timing 228. A fuel control module 232 determines one or more desired fueling parameters 236 based on the torque request 208. The desired fueling parameters 236 may include, for example, a fuel injection amount, a number of fuel injections to inject the amount, and the timing for each of the injections. The fuel actuator module 124 injects fuel based on the desired fueling parameters 236.A desired displacement module 237 determines the desired intake and exhaust cam displacement angles 238 and 239 based on the torque request 208. The phaser actuator module 158 may determine the intake and exhaust cam phasers 148 and 150 based on the desired intake and exhaust cam phaser angles 238 and 239, respectively.As discussed further below, a target wastegate module 240 sets a target wastegate opening 242. The wastegate actuator module 164 controls opening of the wastegate 162 based on the desired wastegate opening 242. For example only, the wastegate actuator module 164 may determine a desired duty cycle (DC) for the wastegate 162 from the desired wastegate opening 242 using a function or mapping that relates desired wastegate openings to desired DCs. Wastegate actuator module 164 may apply a signal to wastegate 162 based on the desired DC.A cylinder control module 244 generates a next cylinder activation / deactivation command 248 in a predetermined firing order of the cylinders ("the next cylinder"). The enable / disable command 248 indicates whether the next cylinder should be enabled or disabled. For example only, the cylinder control module 244 may set the activation / deactivation command 248 to a first state (e.g., 1) if the next cylinder should be activated and set the activation / deactivation command 248 to a second state (e.g., 0) if the next cylinder should be deactivated. While the enable / disable command 248 is treated as being generated for the next cylinder in the predetermined firing order, the enable / disable command 248 may be generated for a second cylinder immediately following the next cylinder in the predetermined firing order, a third cylinder immediately following the second cylinder in the predetermined firing order, or another cylinder immediately following the next cylinder in the predetermined firing order.The cylinder actuator module 120 deactivates the intake and exhaust valves of the next cylinder when the activation / deactivation command 248 indicates that the next cylinder should be deactivated. The cylinder actuator module 120 enables opening and closing of the intake and exhaust valves of the next cylinder when the enable / disable command 248 indicates that the next cylinder should be enabled.The fuel control module 232 interrupts fueling of the next cylinder when the enable / disable command 248 indicates that the next cylinder should be disabled. The fuel control module 232 sets the desired fueling parameters 236 to fueling the next cylinder when the enable / disable command 248 indicates that the next cylinder should be enabled. The desired spark module 224 may provide spark to the next cylinder when the enable / disable command 248 indicates that the next cylinder should be enabled. The desired spark module 224 may provide spark to or stop the next cylinder when the enable / disable command 248 indicates that the next cylinder should be disabled. Cylinder deactivation is different than a fuel deactivation (e.g., deceleration fuel shut-off) in that the intake and exhaust valves of cylinders where fueling is stopped during fuel deactivation may still be opened during fuel deactivation, while the intake and exhaust valves of cylinders are maintained closed when these cylinders are deactivated.The cylinder control module 244 may generate the activation / deactivation command 248 based on a desired firing fraction. A denominator of the target firing fraction corresponds to a target number of (M) cylinders to be activated from the next N cylinders in the predetermined firing order of the cylinders, and N is the denominator of the target firing fraction. A target firing fraction of 5 / 8 indicates, for example, that 5 of the next 8 cylinders should be activated in the previously set firing order. In this example, therefore, 3 of the next 8 cylinders should be deactivated in the predetermined firing order. A target firing fraction of 0 corresponds to all of the deactivated cylinders of engine 102 (and 0 to be activated), and a target firing fraction of 1 corresponds to all of the activated cylinders of engine 102 (and 0 to be deactivated).The cylinder control module 244 may determine the desired firing fraction, for example, based on the torque request 208, an engine speed 252, and a current gear 256 of the transmission 195. For example, the cylinder control module 244 may determine the target firing fraction using one of a function and a mapping that relates torque requests, engine speeds, and gear ratios to target firing fractions. Engine speed 252 may be determined based on, e.g., the crankshaft position measured using crankshaft position sensor 180. The transmission control module 194 may determine the current gear 256, for example, based on signals from one or more transmission sensors within the transmission 195 and / or a position of the manual shift leverAs mentioned above, the wastegate desired module 240 adjusts the wastegate desired opening 242. The target wastegate module 240 may determine the target wastegate opening 242, for example, based on the normal operation torque request 208. The target wastegate module 240 may determine the target wastegate opening 242, for example using a function and mapping that relates torque requests to target wastegate openings. Additionally or alternatively, the target wastegate module 240 may determine the target wastegate opening 242 based on the APP, such as using a function and map that relates APPs to target wastegate openings. For example, the wastegate target module 240 may use interpolation when it is between entries of a map.During normal engine operation, the target wastegate module 240 may adjust the target wastegate opening 242 to decrease if the torque request 208 (and / or the APP) increases and vice versa. The desired wastegate opening 242 may correspond to wastegate 162 when wastegate 162 is fully or maximally closed before torque request 208 reaches a maximum value.Nevertheless, when a trigger signal 260 is generated, the target wastegate module 240 sets the target wastegate opening 242 to a predetermined opening 264. The predetermined opening 264 is a fixed value and may be stored in the memory. The predetermined opening 264 is calibrated and may correspond to a wastegate opening, for example, about 30 percent to 100 percent.A trigger module 268 selectively generates the trigger signal 260. The trigger module 268 generates the trigger signal 260 at times when the driver does not intend to accelerate the vehicle, such as when the transmission 195 is in park or neutral. Additionally or alternatively, the trigger module 268 may generate the trigger signal 260 when the driver has pressed the clutch pedal. By setting the desired wastegate opening 242 to the predetermined opening 264 under such circumstances, the wastegate 162 may be opened or maintained open to allow more natural noise to be emitted from the engine 102 as the driver increases the engine speed 252 (i.e., revolutions of the engine 102) by pressing on the accelerator pedal.As the driver increases engine speed 252 (i.e., revolutions of engine 102) by pressing on the accelerator pedal, determining desired wastegate opening 242 based on torque request 208 (and / or the APP) would cause wastegate 162 to close as discussed above. Closing wastegate 162 prepares engine 102 to increase torque output, but turbocharger turbine 160- 1 also attenuates engine noise.Further operation of the trigger module 268 and the wastegate target module 240 will be discussed in conjunction with FIGS. 3-5. FIG. 3 includes a flowchart including an example method for controlling the wastegate opening to emit more engine noise. The example of FIG. 3 may be used in vehicles with an automatic transmission or other type of transmission. Control begins with 304, where the desired wastegate module 240 determines a wastegate opening based on the torque request 208 and / or the APP using a function and map that relates torque requests and / or APPs to wastegate openings.At 308, the trigger module 268 determines whether the transmission 195 is in park or neutral. For example, trigger module 268 may determine whether transmission 195 is in park or neutral based on whether a PRNDL signal 272 (FIG. 2 ) from PRNDL module 199 (FIG. 1 ) indicates that the driver has commanded transmission 195 to shift to park or neutral via a PRNDL device. The PRNDL device may include, for example, a PRNDL lever, a PRNDL button, one or more physical PRNDL buttons, or one or more PRNDL buttons on a touch screen. As another example, the trigger module 268 may determine whether the transmission 195 is in park or neutral based on whether the current gear ratio 256 is in park or neutral. The current gear ratio 256 may be generated based on signals from one or more sensors within the transmission 195 or based on the manual lever APP within the vehicle cabin.If 308 is true, the target wastegate module 240 sets the target wastegate opening 242 equal to or based on the predetermined opening 264 at 312, and control continues to 320. If 308 is false, the desired wastegate module 240 sets the desired wastegate opening 242 equal to or based on the wastegate opening (at 304) at 316, and control continues to 320. At 320, wastegate actuator module 164 controls the opening of wastegate 162 based on desired wastegate opening 242.Based on the use of the predetermined opening 264, more engine noise may be emitted, including when the driver has applied pressure to the accelerator pedal. For example, if the predetermined opening 264 is used, the wastegate 162 will be more open than the wastegate opening determined at 304 when the driver has applied pressure to the accelerator pedal, for example, to increase the engine speed 252 (and thus accelerate the engine 102). This allows the driver to accelerate engine 102 without closing wastegate 162 to emit more engine noise. While the example of FIG. 3 is shown ending, control may return to 304.FIG. 4 includes a flowchart including an example method for controlling a wastegate opening to emit more engine noise. The example of FIG. 4 may be used in vehicles with manual transmissions or another type of transmission. Control begins with 304, where the desired wastegate module 240 determines a wastegate opening based on the torque request 208 and / or the APP using a function and map that relates torque requests and / or APPs to wastegate openings.At 308, the trigger module 268 determines whether the transmission 195 is in park or neutral. The trigger module 268 may determine whether the transmission 195 is in park or neutral based on whether the current gear step 256 is park or neutral. The current gear ratio 256 may be generated based on signals from one or more transmission sensors within the transmission 195 or based on the manual lever APP within the vehicle cabin. If 308 is true, the target wastegate module 240 sets the target wastegate opening 242 equal to or based on the predetermined opening 264 at 312, and control continues with 320. Based on the use of the predetermined opening 264, more engine noise may be output, including when the driver has applied pressure to the accelerator pedal. If 308 is false, control continues to 404.At 404, the trigger module 268 determines whether the transmission 195 is in a forward or reverse gear stage, such as a reverse gear, a first gear, second gear, third gear, fourth gear, etc. If 404 is true, control continues to 408. If 404 is false, control moves to 316, as explained below. In various applications, 404 may be assumed true in response to determining at 308 that transmission 195 is not in park or neutral. In other words, if 308 is false, control may proceed to 408 and 404 may be omitted.At 408, the trigger module 268 determines whether a vehicle speed 276 (FIG. 2 ) is less than a predetermined speed. If 408 is true, control continues to 412. If 408 is false, control moves to 316, which is discussed below. The ECM 114 may determine the vehicle speed 276 based on, for example, one or more wheel speeds measured by wheel speed sensors. For example, the ECM 114 may determine the vehicle speed 276 based on an average of the speeds of the driven wheels of the vehicle. The predetermined speed may be calibrated and may be, for example, about 5 miles / hr (mph) (about 8 km / hr), or less, or about 10 miles / hr (mph) (about 16 km / hr), or less.At 412, the trigger module 268 may determine whether the driver releases the clutch pedal toward a predefined resting position of the clutch pedal. For example, the trigger module 268 may determine whether a CPP (clutch pedal position) 280 (FIG. 2 ) decreases toward zero (corresponding to the predetermined rest position). The CPP 280 may be measured with one or more CPP sensors that measure the position of the clutch pedal. If 412 is false, the target wastegate module 240 sets the target wastegate opening 242 equal to or based on the predetermined opening 264 at 312, and control will proceed to 320. Based on the use of the predetermined opening 264, more engine noise may be output when the driver has applied pressure to the accelerator pedal. If 412 is true, control may move to 316.At 316, the desired wastegate module 240 sets the desired wastegate opening 242 equal to or based on the wastegate opening determined at 304, and control will proceed to 320. At 320, wastegate actuator module 164 controls the opening of wastegate 162 based on desired wastegate opening 242. While the example of FIG. 4 is shown ending, control may return to 304.FIG. 5 includes a flowchart with an example method for controlling the wastegate opening to emit more engine noise. The example of FIG. 5 may be used in vehicles with manual transmissions or another type of transmission. Control begins with 304, where the desired wastegate module 240 relates a wastegate opening based on the torque request 208 and / or the APP using a function and map that relates torque requests and / or APPs to wastegate openings.At 308, the trigger module 268 determines whether the transmission 195 is in park or neutral. For example, the trigger module 268 may determine whether the transmission 195 is in park or neutral based on whether the current gear step 256 is park or neutral. The current gear ratio 256 may be generated based on signals from one or more sensors gear within the transmission 195 or based on the manual lever APP within the vehicle cabin. If 308 is true, the target wastegate module 240 sets the target wastegate opening 242 equal to or based on the predetermined opening 264 at 312, and control will proceed to 320. Based on the use of the predetermined opening 264, more engine noise may be emitted when the driver has applied pressure to the accelerator pedal. If 308 is false, control continues to 504.At 504, the trigger module 268 determines whether the driver has actuated the clutch pedal at least a predetermined amount. The trigger module 268 may determine whether the CPP 280 is greater than a predetermined position at 504. The predetermined position is greater than zero, where zero corresponds to the predefined resting position of the clutch pedal. If 504 is true, control continues to 508. If 504 is false, control moves to 316, which is discussed below.At 508, the trigger module 268 determines whether a longitudinal acceleration 284 (FIG. 2 ) of the vehicle is within a predetermined acceleration range. The longitudinal acceleration 284 may be measured, for example, with one or more longitudinal acceleration sensors of the vehicle. If 508 is true, control continues to 412. If 508 is false, control moves to 316, as explained below. The predetermined acceleration range may be calibrated and may be, for example, about 0 g and about -0.5 g (i.e., deceleration). This allows the driver to accelerate the engine 102 and obtain increased sound emission, for example during a downshift when a longitudinal deceleration is experienced.At 412, the trigger module 268 may determine whether the driver releases the clutch pedal toward the predefined resting position of the clutch pedal. For example, the trigger module 268 may determine whether the CPP 280 (FIG. 2 ) is decremented from zero. If 412 is false, the target wastegate module 240 sets the target wastegate opening 242 equal to or based on the predetermined opening 264 at 312, and control continues to 320. Based on the use of the predetermined opening 264, more engine noise may be emitted including when the driver has applied pressure to the accelerator pedal. If 412 is true, control may move to 316.At 316, the desired wastegate module 240 sets the desired wastegate opening 242 equal to or based on the wastegate opening determined at 304, and control continues to 320. At 320, wastegate actuator module 164 controls the opening of wastegate 162 based on desired wastegate opening 242. While the example of FIG. 5 is shown ending, control may return to 304.While the example of a single turbocharger is illustrated and described, the foregoing is also applicable to applications with two or more turbochargers, such as parallel and sequential systems of two or more turbochargers. In these applications, the wastegates may be disposed on one, more than one, or all of the turbochargers at the predetermined opening 264 under the foregoing conditions. Further and simultaneously with controlling wastegates of one or more turbochargers at the predetermined opening 264, wastegates of one or more turbochargers (but less than all of the turbochargers) may be controlled based on the desired opening. This may provide a balance between engine sound emission and preparation to increase engine output torque.Also, while the example of controlling the predetermined wastegate opening based on the predetermined opening under the above conditions, the present application is applicable to opening or maintaining open vanes of a variable geometry exhaust turbocharger under the above conditions. Controlling the vanes of the variable geometry exhaust turbocharger as described above in the wastegate control example will provide similar engine noise emission characteristics.

Claims

A turbocharger control method for a vehicle, comprising: generating a trigger signal; in response to generating the trigger signal, setting a target opening of a turbocharger wastegate to a predetermined opening, the predetermined opening being greater than the zero percent opening of the turbocharger wastegate; and actuating the turbocharger wastegate based on the target opening of the turbocharger wastegate; characterized in that the trigger signal is generated when an accelerator pedal is pressurized while a transmission of the vehicle is in a (i) park or a (ii) neutral position.The turbocharger control method according to claim 1, further comprising, when the trigger signal is not generated, setting the target opening of the turbocharger wastegate based on the accelerator pedal position.The turbocharger control method of claim 2, further comprising, when the trigger signal is not generated: decreasing the target opening of the turbocharger wastegate when a driver operates the accelerator pedal away from a predefined accelerator pedal rest position; and increasing the target opening of the turbocharger wastegate when the driver releases the accelerator pedal toward the predefined accelerator pedal rest position.The turbocharger control method of claim 1, wherein the predetermined opening is at least 30 percent opening of the turbocharger wastegate.The turbocharger control method of claim 1, wherein the predetermined opening is less than 100 percent opening of the turbocharger wastegate.The turbocharger control method according to claim 1, further comprising not generating the trigger signal when the clutch pedal moves toward the predefined clutch pedal rest position.The turbocharger control method of claim 1, wherein generating the trigger signal includes generating the trigger signal when all of the following apply: the transmission in a (iii) forward gear or (iv) reverse gear; a clutch pedal is operated away from a predetermined clutch pedal rest position; and a longitudinal acceleration of the vehicle is between a first predefined acceleration and a second predefined acceleration.The turbocharger control method according to claim 7, further comprising not generating the trigger signal when the clutch pedal moves to the predefined clutch pedal rest position.The turbocharger control method according to claim 7, wherein at least one of the first and second predetermined accelerations has a negative value.

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