SYSTEMS AND METHODS FOR GENERATING ADDITIONAL TORQUE

Abstract

Method for controlling a charger (110), comprising: in response to a requested torque (405) exceeding the ignition influence (315) of an engine (10), modifying (335) a current applied to a power unit (140) of the supercharger (110) to provide a quantity of torque (425) to a crankshaft (21) of the engine (10).

Description

AREA

[0001] The present description relates to systems and methods for a supercharger, and more particularly to controlling a supercharger to produce additional torque. BACKGROUND AND SUMMARY

[0002] In response to requested changes in torque output by an engine, the ignition timing can be adjusted to effect the desired change in torque. For example, to decrease the requested torque, the engine is able to reduce the torque by retarding the ignition timing. Similarly, to increase the requested torque, the engine can provide the increased torque by advancing the ignition timing.

[0003] However, the influence on the torque provided by spark timing adjustments, or spark authority, may be limited by combustion instability limits, exhaust temperature limits, minimum time for best torque (MBT), etc. Such limits depend on operating conditions such as load, engine speed, exhaust temperature, throttle position, etc., and are obtained from engine mapping. Furthermore, spark retard increases exhaust temperature, which in turn limits spark authority. As an example, the available spark authority is low during low-speed, high-load operating conditions due to high combustion instability and knock propensity. As a result, a measure of spark authority for a request for spark timing adjustments may be insufficient to achieve a requested torque output.

[0004] US 6 588 256 B2 generally describes the distribution of a torque request across several drive units.

[0005] DE 41 28 642 A1 shows a transmission with several gears.

[0006] US 2010 / 0 275 890 A1 describes a combination of a planetary gear with shafts and electrical machines. When increased or decreased torque is required, the electrical machines are operated as a motor or generator, respectively, to apply additional torque to the crankshaft of an engine via a belt drive.

[0007] The inventors of this disclosure have recognized the above-mentioned disadvantages and developed systems and methods to at least partially address the above problems. In particular, methods and systems for controlling a supercharger according to claims 1, 8, and 10 are provided to generate additional torque. Advantageous further developments emerge from the dependent claims. Accordingly, a method for controlling a supercharger in response to a requested torque that exceeds the firing influence of an engine comprises varying a current applied to a prime mover of the supercharger to provide an amount of torque to a crankshaft of the engine. In this way, a supercharger can be controlled to compensate for a shortfall in engine torque.

[0008] In another embodiment, the system comprises: an engine; a supercharger having a compressor, a planetary gear set coupled to the compressor, a first engine coupled to the engine and further coupled to the planetary gear set, and a second engine coupled to the planetary gear set; and a controller configured with instructions in non-transitory memory that, when executed, cause the controller to vary a current applied to an engine of the supercharger to produce torque applied to at least one component of the system via a mechanical belt. In this manner, a supercharger may be controlled to provide additional torque to an engine when ignition influence is limited.

[0009] Additionally, the cyclic variation resulting from firing events in an internal combustion engine causes vibrations to travel through the driveline, causing transmission clatter and triggering frequencies in the vehicle. In yet another example, a method for controlling a supercharger includes applying a cyclic current to a prime mover of the supercharger, where the prime mover is coupled to an auxiliary device via a mechanical belt. In this way, a supercharger can be controlled to soften torque transients, thereby reducing noise, vibration, and harshness (NVH).

[0010] The above advantages and other advantages and features of the present description will be readily apparent from the following detailed description taken alone or in conjunction with the accompanying drawings.

[0011] It should be understood that the foregoing summary is provided to introduce, in a simplified manner, a selection of concepts that are further described in the detailed description. It is not intended to identify central or essential features of the claimed subject matter, the scope of which is defined solely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that resolve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The advantages described herein will be more fully appreciated by reading an example of an embodiment, referred to herein as the Detailed Description, when considered alone or with reference to the drawings, in which: Fig. 1 shows a block diagram illustrating a vehicle with a supercharger integrated into a powertrain of the vehicle; Fig. Figure 2 shows a block diagram illustrating a vehicle system; Fig. 3 shows a high-level flowchart illustrating an example method for controlling a supercharger to provide additional torque; Fig. 4 an exemplary operating procedure according to the procedure of Fig. 3 shows; Fig. 5 shows a high-level flow diagram illustrating an exemplary method for controlling a supercharger to provide additional cyclic torque; and Fig. 6 an exemplary operating procedure according to the procedure of Fig. 5 is. DETAILED DESCRIPTION

[0013] The present description relates to a supercharger. In particular, methods and systems for controlling a supercharger to generate additional torque and mitigate torque transients are provided. The supercharger may include a planetary gear set and two prime movers to provide a fully variable transmission (as distinct from the transmission that couples the engine to the vehicle wheels) and may be integrated into a vehicle system as described in Fig. 1-2. The supercharger can be controlled to increase the ignition influence by providing additional torque to an engine crankshaft, as shown in Fig. 3. An example timeline for providing the additional torque is shown in Fig. 4. The supercharger can also be controlled to provide cyclic torque to FEAD devices and thus torque transitions from the engine, as shown in Fig. 5. An exemplary timeline for providing the cyclic torque is shown in Fig. 6 shown.

[0014] Fig. 1 shows a schematic diagram of a vehicle system 100 having a supercharger 110 mounted on an engine 10. The vehicle system 100 further includes an energy storage device or battery 46, a transmission 44, wheels 52, a fuel system 20, one or more auxiliary devices 19, and a control system 14.

[0015] The input shaft 131 of the supercharger 110 is mechanically coupled to the crankshaft 21 of the engine 10 via a belt 31. Although not shown, the inlet of the compressor 180 is connected to draw air through an air filter, as is known in the art. However, it should be noted that in some embodiments, the input shaft 131 of the supercharger 110 may be coupled to the crankshaft 21 through any suitable connection. For example, a gear drive arrangement may also be used.

[0016] The supercharger 110 is also mechanically coupled via belt 33 to an auxiliary device 19 to provide a front-end accessory drive (FEAD). The mechanically driven auxiliary device may be a water pump, a power steering pump, a vacuum pump, an air pump, or another mechanically driven device (e.g., a FEAD device).

[0017] The supercharger 110 includes a first engine generator 140 and a second engine generator 150, which are housed in a housing of the supercharger 110. The supercharger 110 further includes a planetary gear set 160 provided between the two engine generators 140, 150. The input shaft 131 of the supercharger 110 is coupled to the rotor (not shown) of the first engine generator 140. The rotor of the first engine generator 140 is further coupled via the shaft 132 to the ring gear (not shown) of the planetary gear set 160. In some examples, the shaft 132 and the input shaft 131 comprise a common shaft. The driver (not shown) of the planetary gear set 160 is coupled via the shaft 151 to the rotor (not shown) of the second engine generator 150. As shown, the belt 33 is coupled to the FEAD or the auxiliary device 19 is coupled to the supercharger 110 via the shaft 151.

[0018] The output shaft 170 of the supercharger 110 is coupled to the sun gear (not shown) of the planetary gear set 160 and the compressor 180. As one example, the output shaft 170 may be coupled to the impeller (not shown) of the compressor 180. In some examples, the shaft 151 may be hollow so that the shaft 170 may extend therethrough to the compressor 180. At the output end of the supercharger 110, the output of the compressor 180 is connected to an intake manifold 124 of the engine 10.

[0019] In some examples, the speed of the first engine-generator 140 is fixedly connected to the engine speed, while the second engine-generator 150 is free to rotate relative to the first engine-generator 140 and the engine 10. When the second engine-generator 150 and the follower to which it is coupled are fixed, the planetary gear set 160 acts to rotate the sun gear, and thus the output shaft 170 and the impeller of the compressor 180, faster than the ring gear, and thus faster than the input shaft 131, the first engine-generator 140, and the engine 10 to which the ring gear is coupled. However, when the second engine-generator 150 is operated to rotate in a direction opposite that of the first engine-generator 140, the planetary gear set 160 acts to rotate the impeller even faster.When the second engine-generator 150 is operated to rotate in the same direction as the first engine-generator 140, the planetary gear set 160 acts to rotate the impeller more slowly. Thus, the second engine-generator 150 can be used to increase or decrease the speed of the impeller relative to the speed of the input shaft 131 and thus the engine 10, and can thus vary the air pressure in the intake manifold 124, also known as boost pressure.

[0020] Alternatively, in some examples, as further described herein with reference to Fig. 3-4, to provide additional torque to the crankshaft 21 of the engine 10 via the belt 31. In other examples, as further described herein with reference to Fig. 5-6, the second engine-generator 150 may be driven to smooth torque transients. In such examples, the supercharger 110 may include a one-way clutch 171 on the output shaft 170 to selectively engage and disengage the planetary gear set 160 from the compressor 180, for example, to avoid pulsing of airflow in the intake manifold 124 when the second engine-generator 150 is controlled to smooth torque transients.

[0021] Furthermore, the charger 110 may be coupled to the vehicle's battery 46 and may be configured to charge the battery 46 during engine operation. For example, the charger 110 may be configured to convert the mechanical energy generated while the engine 10 is running into electrical energy for storage in the battery 46. This allows the charger 110 to act as a generator and / or an alternator / starter of the vehicle system 100.

[0022] The engine 10 is coupled to the transmission 44. The transmission 44 may include a manual transmission, an automatic transmission, or combinations thereof. The transmission 44 may include a gear set with a plurality of gears. Various additional components may also be included, such as a torque converter, a final drive unit, etc. The transmission 44 is shown coupled to the drive wheels 52, which may contact a road surface.

[0023] The vehicle system 100 further includes a control system 14. The control system 14 is shown receiving information from a plurality of sensors 16 (for the various examples shown in Fig. 2) and sends control signals to a plurality of actuators 81 (for the various examples described in Fig. 2). As an example, the sensors 16 may include various pressure and temperature sensors, a fuel level sensor, various exhaust gas sensors, torque sensors, etc. The control system 14 may also send control signals to the actuators 81 based on input received from a vehicle operator and the plurality of sensors 16. The various actuators may include, for example, the transmission, transmission gears, cylinder fuel injectors, an air intake throttle coupled to the engine intake manifold, the first engine generator 140, the second engine generator 150, the planetary gear set 160, etc. The control system 14 may include a controller 12.The controller may receive input data from the various sensors or buttons, process the input data, and trigger the actuators in response to the processed input data based on instructions or code programmed therein according to one or more routines. Example control routines are described with respect to . Fig. 3 and Fig. 5 described.

[0024] The combustion engine 10 is furthermore designed with regard to Fig. 2, which shows a schematic block diagram illustrating a vehicle system 200 with the engine 10. The internal combustion engine 10, which includes a plurality of cylinders, one cylinder in Fig. 2, is controlled by an electronic engine controller 12. The engine 10 includes the combustion chamber 30 and cylinder walls 32 with the piston 36 disposed therein and is connected to the crankshaft 40. The combustion chamber 30 is shown in communication with the intake manifold 44 and the exhaust manifold 48 via a respective intake valve 52 and exhaust valve 54. Each intake and exhaust valve can be actuated independently with respect to valves of other cylinders via the intake cam 51 and exhaust cam 53. The intake valve timing device 85 advances or retards the phase of the intake valve 52 with respect to a position of the crankshaft 40. Additionally, the intake valve timing device 85 can increase or decrease an intake valve lift amount. An exhaust valve timing device 83 advances or retards the phase of the exhaust valve 54 with respect to a position of the crankshaft 40.Furthermore, the exhaust valve adjuster 83 can increase or decrease an exhaust valve lift amount. The position of the intake cam 51 can be determined by the intake cam sensor 55. The position of the exhaust cam 53 can be determined by the exhaust cam sensor 57.

[0025] A fuel injector 66 is shown arranged to inject fuel directly into the cylinder 30, known to those skilled in the art as direct injection. Alternatively, the fuel may be injected into an intake port, known to those skilled in the art as port injection. The intake manifold 44 is shown in conjunction with the optional electronic throttle 62, which adjusts a position of the throttle plate 64 to control airflow from a boost chamber 46 to the intake manifold 44. In some examples, the throttle 62 and throttle plate 64 may be positioned between the intake valve 52 and the intake manifold 44 such that the throttle 62 is a single throttle. The compressor 162 supplies air from the air intake 42 to the boost chamber 46. The compressor 162 is driven by the shaft 161, which is mechanically coupled to the turbine 164. The compressor bypass valve 158 can be selectively operated to reduce the boost pressure.The wastegate 72 can be selectively opened and closed to control the speed of the turbine 164.

[0026] The distributorless ignition system 88 provides an ignition spark to the combustion chamber 30 via the spark plug 92 in response to the controller 12. The universal exhaust gas oxygen (UEGO) sensor 126 is shown coupled to the exhaust manifold 48 upstream of the turbine 164 and the catalyst 70. Alternatively, a dual-state oxygen sensor may replace the wideband oxygen sensor 126. The catalyst 70, in one example, may include multiple catalyst bricks. In another example, multiple emission control devices, each with multiple bricks, may be used. The catalyst 70, in one example, may be a three-way catalyst.

[0027] The control 12 is in Fig. 2 as a conventional microcomputer including: a microprocessor unit 102, input / output ports 104, a (non-volatile) read-only memory 106, a random access memory 108, a keep-alive memory 110, and a conventional data bus. The controller 12 is shown receiving various signals from sensors coupled to the engine 10, in addition to the signals previously discussed, including: an engine coolant temperature (ECT) from temperature sensor 112 coupled to cooling sleeve 114; a measurement of engine manifold pressure (MAP) from pressure sensor 121 coupled to intake manifold 44; a measurement of boost pressure from pressure sensor 122; an engine position sensor from a Hall-effect sensor 118 that senses the position of the crankshaft 40; and a measurement of air mass entering the engine from sensor 120; and a measurement of throttle position from sensor 58.The barometric pressure may also be sensed to be processed by the controller 12 (sensor not shown).

[0028] During operation, each cylinder within the engine 10 typically undergoes a four-stroke cycle: The cycle includes the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. During the intake stroke, the exhaust valve 54 closes and the intake valve 52 generally opens. Air is directed through the intake manifold 44 into the combustion chamber 30, and the piston 36 moves toward the bottom of the cylinder to increase the volume within the combustion chamber 30. The position where the piston 36 is near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber 30 has reached its largest volume) is commonly referred to by those skilled in the art as bottom dead center (BDC). During the compression stroke, the intake valve 52 and the exhaust valve 54 are closed. The piston 36 moves toward the cylinder head to compress the air within 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 has reached its smallest volume) is commonly referred to by those skilled in the art as the top dead center (TDC).

[0029] 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 devices, such as spark plug 92, resulting in combustion. During the power stroke, the expanding gases push the piston 36 back to BDC. The crankshaft 40 converts the piston motion into rotating shaft torque. Finally, during the exhaust stroke, the exhaust valve 54 opens to release the combusted air-fuel mixture to the exhaust manifold 48, and the piston returns to TDC. It should be noted that the above is shown only as an example, and that intake and exhaust valve opening and / or closing timing may vary to provide positive or negative intake and exhaust valve opening overlap, late intake valve closing, and various other examples.

[0030] The driver's torque demand may be determined via a position of an accelerator pedal 130, which is sensed by an accelerator pedal sensor 134. A voltage or current indicative of the driver's torque demand is output by the accelerator pedal sensor 134 when the driver's foot 132 depresses the accelerator pedal 130.

[0031] In response to changes in the driver's torque demand, spark timing can be advanced or retarded to achieve the desired change in torque. For example, to reduce the driver's torque demand, the engine is able to reduce torque by retarding spark timing. However, the torque influence provided by spark timing, or spark authority, may be insufficient to achieve the requested torque change. The extent of spark influence for each spark retard / advance request may be limited by combustion instability limits, exhaust temperature limits, and minimum time to best torque (MBT), as non-limiting examples. Furthermore, spark retard increases exhaust temperature, which in turn limits spark influence.The available ignition influence is low during low-speed, high-load operating conditions due to high combustion instability and knock tendency. As further discussed herein with respect to . Fig. 3, a method for compensating for a loss of torque due to ignition influence limitations includes controlling a supercharger to provide additional torque.

[0032] Fig. 3 shows a high-level flowchart illustrating an exemplary method 300 for providing additional torque according to one embodiment. In particular, method 300 relates to controlling a booster to achieve a requested torque when ignition influence is limited. Method 300 is described herein with reference to the components and systems described in Fig. 1 and Fig. 2, but it should be understood that the method may be applied to other systems without departing from the scope of this disclosure. Method 300 may be executed by controller 12 and may be stored as executable instructions in non-volatile memory.

[0033] Method 300 begins at 305. At 305, method 300 includes evaluating operating conditions. The operating conditions may include, among other things, engine speed, spark timing, exhaust temperature, torque demand, throttle position, engine load, etc. The operating conditions may be measured by one or more sensors 16 coupled to controller 12, or may be estimated or inferred based on available data.

[0034] Continuing at 310, method 300 includes determining whether there is a change in torque demand. In one example, the torque demand may be assessed at 305 based, for example, on a sensed accelerator pedal position, such as the position of accelerator pedal 130 sensed by accelerator pedal sensor 134, as discussed hereinabove with respect to Fig. 2, although it will be understood that torque demand may additionally or alternatively be based on other operating conditions, such as engine load. In one example, a change in torque demand may include an increase or decrease in torque demand relative to a previous torque demand.

[0035] The method may determine that there is no change in torque demand ("NO") if the currently requested torque is within a threshold range of a previous torque demand, while the method may determine that there is a change in torque demand ("YES") if the currently requested torque is outside the threshold range of the previous torque demand. The threshold range may be small so that small changes in torque demand over time can be ignored for the purposes of the present method. However, in some examples, the method may simply determine whether the currently requested torque is the same as the previously requested torque ("NO") or whether the currently requested torque is different from the previously requested torque at all ("YES").

[0036] If there is no change in torque demand ("NO"), method 300 proceeds to 312. At 312, method 300 includes maintaining operating conditions, such as the operating conditions evaluated at 305. Then, method 300 may end or return to 305, for example. In this way, method 300 may monitor operating conditions for a change in torque demand.

[0037] Referring back to 310, if there is a change in torque demand (“YES”), method 300 proceeds to 315. At 315, method 300 includes determining whether the torque demand exceeds the spark influence. The amount of spark influence for each spark retard / advance request may be limited by combustion instability limits, exhaust temperature limits, minimum time for best torque (MBT), as non-limiting examples. Further, spark retard increases exhaust temperature, which in turn limits spark influence. Available spark influence is low during low speed, high load operating conditions due to high combustion instability and knock propensity. Thus, in one example, determining whether the torque demand exceeds the spark influence includes determining whether spark timing can be adjusted to meet the torque demand.

[0038] If the torque demand does not exceed the spark influence ("NO"), method 300 proceeds to 317. At 317, method 300 includes adjusting spark timing based on the torque demand. For example, spark timing is adjusted to meet the torque demand. Method 300 then ends.

[0039] However, referring again to 315, if the torque demand exceeds the spark input ("YES"), method 300 proceeds to 320. At 320, method 300 determines whether additional boost meets the torque demand. For example, if the spark input is very limited and a loss of torque output is imminent, additional boost may not be sufficient to satisfy the torque demand because controlling the compressor to produce additional boost may be too slow. To meet the torque demand, controlling the supercharger to produce additional torque may preferably be controlling the supercharger to produce additional boost. However, if the spark input is not too limited, the compressor may be controlled to produce additional boost in a timely manner to meet the torque demand.

[0040] Thus, if the additional boost pressure meets the torque demand ("YES"), method 300 proceeds to 322. At 322, method 300 adjusts spark timing and the compressor to generate additional boost pressure for the engine based on the torque demand. Method 300 then ends.

[0041] However, referring back to 320, if the additional boost pressure does not meet the torque demand ("NO"), method 300 proceeds to 325. At 325, method 300 includes calculating a desired additional torque based on the torque demand and the spark influence. In one example, the desired additional torque includes a difference between the total desired torque (i.e., the torque demand) and the maximum available torque through spark retard / advance (i.e., the spark influence limits).

[0042] At 330, method 300 includes adjusting spark timing based on the torque demand. Specifically, spark timing is adjusted to the spark influence limits, beyond which spark timing cannot be further adjusted to provide at least a portion of the requested torque. In some examples, spark timing may already be adjusted to the spark influence limits, and thus, no further spark timing adjustment occurs at 330.

[0043] At 335, method 300 includes adjusting one or more operating parameters of the supercharger based on the desired additional torque. For example, at 335, the first engine of the supercharger is controlled to provide mechanical torque to the engine crankshaft to assist the engine in meeting the torque demand. In one example, the controller varies the current applied to the first engine such that the first engine produces the desired additional torque.

[0044] It should be noted that the additional torque generated by the first prime mover and applied to the engine crankshaft can be considered positive or negative. For example, if the torque demand is an increase in the current engine torque, the first prime mover can be controlled to rotate in the same direction as the engine crankshaft so that the first prime mover provides positive torque (i.e., the additional torque is added to the engine torque). Similarly, if the torque demand is a decrease in the current engine torque, the first prime mover can be controlled to rotate in an opposite direction to the engine crankshaft so that the first prime mover provides negative torque (i.e., the additional torque is subtracted from the engine torque).

[0045] In some examples, the method may adjust the gear ratio of the supercharger's planetary gear set such that the first engine applies the additional torque to the crankshaft while the compressor continues to operate normally. Thus, adjusting one or more operating parameters may further include selectively controlling the gear ratio of the supercharger's planetary gear set.

[0046] In some alternative examples, the compressor of the supercharger may be disconnected from other components of the supercharger (e.g., the planetary gear set and the engine generators) (e.g., via a one-way clutch 171) while controlling the supercharger to provide additional torque. Adjusting one or more operating parameters may thus further include selectively disengaging a one-way clutch and / or the planetary gear set of the supercharger.

[0047] After adjusting the operation of the supercharger, method 300 may then return to 305 to continue monitoring for changes in torque demand.

[0048] Thus, a method for controlling a supercharger to provide additional torque is disclosed. It will be appreciated that in some examples, the additional torque may be provided only for short periods of time to avoid excessive current drain from the battery.

[0049] Although not shown, it will be understood that in some examples, method 300 may include operations that take into account the operating conditions of the supercharger. For example, method 300 may further include determining whether the first engine of the supercharger is available to provide additional torque to the engine crankshaft prior to calculating the desired additional torque. In some examples, the method may not utilize the supercharger to provide additional torque if the supercharger is unavailable. Additionally or alternatively, in some examples, for example, when the supercharger is boosting (i.e., the first and second engines are controlled to provide compressed / charged air to the engine intake), the current operation of the supercharger may be temporarily interrupted (e.g., by disengaging one-way clutch 171) to provide the additional torque.

[0050] Fig. 4 shows an exemplary timeline 400 for providing the additional torque using the method described herein with reference to Fig. 3. Timeline 400 includes curve 405, which indicates torque demand (e.g., the instantaneous amount of torque requested or demanded for vehicle operation) over time. Timeline 400 also includes curve 415, which indicates crankshaft torque (e.g., the instantaneous torque provided to the transmission by the engine) over time. Timeline 400 also includes curve 425, which indicates booster torque (e.g., the instantaneous torque provided to the engine crankshaft by the booster) over time. Crankshaft torque and booster torque cooperate to provide total torque to the transmission. Thus, timeline 400 also includes curve 417, which indicates total crankshaft torque (e.g., the total torque provided to the transmission and produced by the engine and the booster) over time.

[0051] At time T0, the torque demand is equal to a value A, as indicated by curve 405 of diagram 401. Furthermore, the crankshaft torque provided to the transmission is equal to A, as indicated by curves 415 and 417. The agreement of curves 415 and 417 indicates that the engine is producing sufficient torque to meet the torque demand. Thus, the torque provided to the crankshaft by the supercharger is zero, as indicated by curve 425.

[0052] From time T1 to T3, the torque demand increases linearly from A to B, as indicated by curve 405. Such an increase in torque demand may occur in response to increased throttle pedal position, as a non-limiting example. In response, engine operation is adjusted (e.g., spark timing is adjusted) to increase the torque provided by the engine. Thus, from T1 to T2, the crankshaft torque provided by the engine increases from A to D, as indicated by curve 415. However, torque D is less than the requested torque B. Thus, at time T2, the torque provided by the engine is insufficient to meet the torque demand indicated by curve 405. To fill this torque deficit or torque gap, the supercharger is controlled at time T2 to provide torque to the engine crankshaft, as indicated by curve 425.As shown, the supercharger torque increases linearly from zero torque to a torque equal to the difference between torque B and torque D (i.e., BD). Consequently, the total torque delivered to the transmission from the crankshaft (the combination of the engine torque indicated by curve 415 and the supercharger torque indicated by curve 425) is equal to the demanded torque, as indicated by curve 417.

[0053] From time T3 to T4, the torque demand is constant and equal to B, as indicated by curve 405. The engine torque is still insufficient to meet the torque demand, as indicated by curve 415, and thus the supercharger continues to provide additional torque to the crankshaft, as indicated by curve 425. Consequently, the total torque provided to the transmission by the crankshaft is equal to the demanded torque, as indicated by curve 417.

[0054] From time T4 to T6, the torque demand decreases from B to C, as indicated by curve 405. The supercharger continues to provide additional torque to the crankshaft to meet the torque demand until the engine torque is sufficient to provide the requested torque at T5, when the torque demand reaches value D, above which the engine can no longer supply on its own due to ignition influence limitations.

[0055] Thus, from time T4 to T5, the supercharger torque drops from (BD) to zero, while the engine torque remains constant at D, as indicated by curves 425 and 415, respectively, so that the total torque provided to the transmission from the crankshaft is equal to the demanded torque, as indicated by curves 417 and 405, respectively.

[0056] From time T5 to T6, the torque demand decreases from D to C while the supercharger provides no torque, as indicated by curves 415 and 425, respectively. At time T6, the torque demand is balanced at a constant value C, as indicated by curve 405. The engine torque provides the torque demand without additional torque from the supercharger, as indicated by curves 415, 417, and 425, respectively.

[0057] Thus, systems and methods are provided for filling the torque gap and increasing ignition influence. It is understood that the Fig. 4 is exemplary and not limiting and is provided to illustrate an example of how a supercharger may be used to provide additional torque when ignition influence is limited.

[0058] Fig. 5 shows a high-level flowchart illustrating an example method 500 for controlling a supercharger to provide additional cyclic torque, according to one embodiment. In particular, method 500 relates to controlling a supercharger to mitigate torque transients in auxiliary or FEAD devices. Method 500 is described herein with reference to the components and systems described in Fig. 1 and Fig. 2, but it should be understood that the method may be applied to other systems without departing from the scope of this disclosure. Method 500 may be executed by controller 12 and may be stored as executable instructions in non-volatile memory.

[0059] Method 500 begins at 505. At 505, method 500 includes evaluating operating conditions. The operating conditions may include, but are not limited to, engine speed, spark timing, exhaust temperature, torque demand, accelerator pedal position, throttle position, engine load, etc. The operating conditions may be measured by one or more sensors 16 coupled to controller 12, or may be estimated or inferred based on available data.

[0060] At 510, method 500 includes determining whether a firing event has occurred. For example, a firing event occurs when a spark plug ignites fuel in a cylinder. If no firing event has occurred ("NO"), method 500 proceeds to 512. At 512, method 500 includes maintaining operating conditions. Method 500 then ends.

[0061] However, if a firing event occurred at 510 ("YES"), method 500 proceeds to 515. At 515, method 500 includes controlling a second prime mover of a supercharger to provide cyclic torque to FEAD accessories. In one example, the drive current and frequency provided to the second prime mover are varied to provide cyclic drive torque from the mechanical belt. This drive torque is operated in phase with engine power, thereby absorbing power during peak acceleration rather than during engine deceleration. By absorbing mechanical torque during peak accelerations, engine sway is smoothed and the impact of NVH is reduced.

[0062] At 520, method 500 optionally includes controlling a one-way clutch to minimize speed variation in the compressor. For example, one-way clutch 161 of supercharger 110 may be disengaged so that the cyclic torque provided by second engine 150 does not affect compressor 180. Method 500 then ends.

[0063] Fig. 6 shows an exemplary timeline 600 for providing the additional torque to FEAD devices according to the method of Fig. 5. Timeline 600 includes curve 605, which indicates crankshaft acceleration over time. Timeline 600 also includes curve 615, which indicates torque delivered to the FEAD devices over time, and curve 625, which indicates current delivered to the supercharger over time.

[0064] Following a firing event, the crankshaft acceleration (e.g., engine acceleration) may be sinusoidal, as illustrated by curve 605. The cyclic variation resulting from the firing events in the engine causes vibrations to travel through the powertrain, causing transmission clatter and triggering frequencies in the vehicle. A cyclic current is provided to the supercharger, for example, the current provided by the controller 12 to the second engine 150 of the supercharger 110, as indicated by curve 625. The cyclic supercharger current drives the second engine of the supercharger to provide cyclic torque applied to the FEAD devices, as indicated by curve 615. The cyclic current, and consequently the cyclic torque, are driven in phase with the crankshaft acceleration 605 so that the FEAD torque provides power during peak engine acceleration (e.g.,peaks of curve 605) and not absorbed during engine deceleration.

[0065] Thus, systems and methods are provided for controlling a variable speed drive mechanism for FEAD devices so that high-load components consume maximum power during peak engine acceleration and a lesser amount during engine deceleration following the ignition event. In one example, the drive mechanism includes a supercharger as described hereinabove, but it will be understood that any high-torque, variable speed drive device may be used in accordance with the systems and methods described herein without departing from the scope of the present disclosure.

[0066] In one embodiment, a method for controlling a supercharger in response to a requested torque that exceeds the firing influence of an engine includes varying a current applied to a motor of the supercharger to provide an amount of torque to a crankshaft of the engine.

[0067] In a first example of the method, the method further comprises calculating an engine torque based on the ignition influence and calculating the amount of torque based on the engine torque and the requested torque. In a second example of the method, optionally including the first example, the amount of torque comprises a difference between the requested torque and the engine torque. In a third example of the method, optionally including one or more of the first and second examples, the method further comprises adjusting the ignition timing of the engine to produce the calculated engine torque. In a fourth example of the method, optionally including one or more of the first through third examples, the engine is coupled to the engine crankshaft via a mechanical belt.In a fifth example of the method, optionally including one or more of the first through fourth examples, the amount of torque provided to the crankshaft cooperates with the torque produced by the engine to produce the requested torque. In a sixth example of the method, optionally including one or more of the first through fifth examples, the engine of the supercharger is coupled to a planetary gear set of the supercharger, the planetary gear set further coupled to a compressor of the supercharger, and the method further comprises selectively disengaging the planetary gear set from the compressor while varying the current.

[0068] In another embodiment, a method for controlling a supercharger comprises applying a cyclic current to a prime mover of the supercharger, wherein the prime mover is coupled to an auxiliary device via a mechanical belt.

[0069] In a first example of the method, the method further comprises applying the cyclic current in response to a firing event in an engine coupled to the supercharger. In a second example of the method, optionally including the first example, the cyclic current is based on torque produced by an engine. In a third example of the method, optionally including one or more of the first and second examples, the cyclic current is synchronized in phase with peak accelerations of an engine coupled to the supercharger. In a fourth example of the method, optionally including one or more of the first through third examples, the engine is coupled to a first engine of the supercharger, and wherein the engine is coupled to the first engine via a planetary gear set of the supercharger.In a fifth example of the method, optionally including one or more of the first through fourth examples, the method further comprises selectively disengaging the planetary gear set from a compressor of the supercharger while applying the cyclic current to the engine. In a sixth example of the method, optionally including one or more of the first through fifth examples, selectively disengaging the planetary gear set from the compressor comprises selectively disengaging a one-way clutch between the planetary gear set and the compressor.

[0070] In yet another embodiment, the system comprises: an engine; a supercharger having a compressor, a planetary gear set coupled to the compressor, a first prime mover coupled to the engine and further coupled to the planetary gear set, and a second prime mover connected to the planetary gear set; and a controller configured with instructions in non-transitory memory that, when executed, cause the controller to: vary a current applied to a prime mover of the supercharger to produce torque applied to at least one component of the system via a mechanical belt.

[0071] In a first example of the system, the at least one component of the system includes a crankshaft of the engine, the prime mover of the supercharger includes the first prime mover, and the mechanical belt couples the first prime mover to the crankshaft. In a second example of the system, optionally including the first example, the controller is further configured with instructions in the non-transitory memory that, when executed, cause the controller to: calculate, in response to a requested torque, additional torque based on the requested torque and a firing bias of the engine; and vary the current applied to the first prime mover based on the calculated additional torque.In a third example of the system, optionally including one or more of the first and second examples, the system further comprises an auxiliary device, wherein the at least one component of the system comprises the auxiliary device, the prime mover comprises the second prime mover, and the mechanical belt couples the second prime mover to the auxiliary device. In a fourth example of the system, optionally including one or more of the first to third examples, the current applied to the prime mover comprises a cyclic current in phase with the power output of the engine.In a fifth example of the method, optionally including one or more of the first to fourth examples, the supercharger further includes a one-way clutch, wherein the planetary gear set is coupled to the compressor via the one-way clutch, and wherein the controller further includes instructions in the non-volatile memory that, when executed, cause the controller to selectively disengage the one-way clutch while varying the current.

[0072] The control routines, as in Fig. 3 and Fig.5 may be used together and may further include various additional operations. During some conditions, such as lower temperatures of the supercharger planetary gear set (which may be measured by a temperature sensor coupled to the transmission and / or estimated based on other temperature sensors, such as engine temperature and air temperature), the method may rely to a greater extent on adjusting the supercharger gear ratio to thereby adjust engine crankshaft torque. However, during higher supercharger transmission temperatures, the method may rely to a greater extent on spark adjustments (rather than gear ratio adjustments).In this way, the system can still provide the desired crankshaft torque control while also reducing potential wear deterioration on the turbocharger transmission at higher temperatures. Furthermore, a lower transmission temperature is likely to be associated with lower engine temperatures, reducing the potential for knock and allowing greater reliance on ignition control.

[0073] It should be noted that the exemplary control and estimation routines contained herein may be used with various engine and / or vehicle system configurations and / or various alternator / starter configurations contained herein. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and may be executed by the control system, including the controller in combination with various sensors, actuators, and other vehicle system hardware. The particular routines described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like.As such, various illustrated acts, operations, and / or functions may be performed in the illustrated order, in parallel, or in some cases omitted. Likewise, the processing order is not required to achieve the features and advantages of the embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated acts, operations, and / or functions may be performed repeatedly, depending on the particular strategy employed. Furthermore, at least a portion of the described acts, operations, and / or functions may graphically represent code to be programmed into non-transitory memory of the computer-readable storage medium in the control system.The control operations may also transform the operating state of one or more sensors or actuators in the physical world if the described actions are performed by executing the instructions in a system that includes the various vehicle hardware components in combination with one or more controllers.

[0074] This concludes the description. Upon reading this description, those skilled in the art will be aware of various changes and modifications without departing from the spirit and scope of the description. For example, I3, I4, I5, V6, V8, V10, V12, and horizontally opposed engines operating on natural gas, gasoline, diesel, or alternative fuel configurations could advantageously utilize the present description.

Claims

[1] A method for controlling a charger (110), comprising: in response to a requested torque (405) exceeding the ignition influence (315) of an engine (10), varying (335) a current applied to an engine (140) of the supercharger (110) to provide an amount of torque (425) to a crankshaft (21) of the engine (10). [2] The method of claim 1, further comprising calculating (325) an engine torque based on the ignition influence and calculating (325) the torque amount (425) based on the engine torque (415) and the requested torque (405). [3] The method of claim 2, wherein the torque amount (425) comprises a difference between the requested torque (405) and the engine torque (415). [4] The method of claim 2, further comprising adjusting (317) the ignition timing of the engine (10) to produce the calculated engine torque (415). [5] The method of claim 1, wherein the engine (140) of the supercharger is coupled to the crankshaft (21) via a mechanical belt (31). [6] The method of claim 1, wherein the amount of torque (425) provided to the crankshaft (21) cooperates with the torque (415) produced by the engine (10) to provide the requested torque (405). [7] The method of claim 1, wherein the prime mover (140) of the supercharger (110) is coupled to a planetary gear set (160) of the supercharger (110), the planetary gear set (160) further coupled to a compressor (180) of the supercharger (110), and further comprising selectively adjusting (335) a gear ratio of the planetary gear set (160) while varying the current. [8] A method for controlling a charger, comprising: Applying (515) a cyclic current (625) to a prime mover (150) of the supercharger, the prime mover being coupled to an auxiliary device via a mechanical belt, the prime mover providing a cyclic torque to the auxiliary device via the mechanical belt in dependence on the cyclic current. [9] The method of claim 8, wherein the cyclic current (625) is synchronized in phase with peak accelerations (605) of an engine (10) coupled to the supercharger (110), and wherein the current (625) is further adjusted in response to a temperature of a planetary gear set of the supercharger coupling the supercharger (110) to a crankshaft (21) of the engine (10). [10] System (100) comprising: an engine (10); a supercharger (110) having a compressor (180), a planetary gear set (160) coupled to the compressor (180), a first engine (140) coupled to the engine (10) and further to the planetary gear set (160), and a second engine (150) coupled to the planetary gear set (160); and a controller (12) configured with instructions in a non-volatile memory that, when executed, cause the controller (12): vary (335) a current applied to a prime mover (140, 150) of the supercharger (110) to produce additional torque applied to a crankshaft of the engine via a mechanical belt (31, 33) when an engine torque output of the engine reaches a maximum available torque, the additional torque comprising a difference between the requested torque and the maximum available torque. [11] The system (100) of claim 10, wherein the prime mover (140, 150) of the supercharger (110) comprises the first prime mover (140) and the mechanical belt (31) couples the first prime mover (140) to the crankshaft (21). [12] The system (100) of claim 11, wherein the controller (12) is further configured with instructions in the non-volatile memory that, when executed, cause the controller (12): in response to the requested torque, calculate (325) the additional torque based on the requested torque and a firing influence of the engine (10); and to change (335) the current applied to the first prime mover (140) based on the calculated additional torque. [13] The system (100) of claim 10, further comprising an auxiliary device (19), wherein the controller is further configured with instructions in non-volatile memory that, when executed, cause the controller to vary a current applied to the second prime mover to produce a cyclic torque applied to the auxiliary device via a second mechanical belt. [14] The system of claim 13, wherein the current applied to the second prime mover (150) comprises a cyclic current (625) in phase with the power output (605) of the engine (10). [15] The system of claim 13, wherein the supercharger (110) further includes a one-way clutch (171), the planetary gear set (160) being coupled to the compressor (180) via the one-way clutch (171), and wherein the controller (12) further includes instructions in the non-volatile memory that, when executed, cause the controller (12) to selectively disengage (520) the one-way clutch (171) while changing the current (515).

Images