System and methods improving gear shifting of a transmission

Systems and methods for improving shifting of a transmission are described. The systems and methods may be applied to automatic or manual transmissions, but the systems and methods may be particularly suited for automatic transmissions. In one example, electrical input to an alternator and electrical output from the alternator is adjusted in response to a request to upshift a transmission.

FIELD

The present description relates to a system and methods for improving gear shifting of a transmission via controlling operation of an alternator. The system and methods may be suitable for vehicles that include an automatic or a manual transmission.

BACKGROUND AND SUMMARY

A vehicle's transmission may be upshifted or downshifted from time to time to improve engine efficiency and vehicle performance. During an upshift the transmission is shifted from a lower gear (e.g., first gear) to a higher gear (e.g., second gear). At a time just before the upshift, the vehicle's engine is rotating at a first speed and the vehicle's wheels are rotating at a second speed that is a function of engine speed and a ratio of the lower gear. Because of a ratio difference between the lower gear and the higher gear, engine speed may be reduced during the upshift so that when the higher gear is engaged, a large torque disturbance does not occur within the driveline. In particular, the engine speed may be reduced to a speed that is a function of the wheel speed and the higher gear ratio so that when the higher gear is engaged, a smooth shift may be performed with a reduced torque disturbance in the driveline. One way to reduce engine speed is to at least partially close the engine's throttle so that engine torque may be reduced, but engine speed may not be reduced to the new speed fast enough to provide a smooth shift. Therefore, it may be desirable to provide a way of improving transmission shifting. Also, it has been noted that a fast shift, which is aided by a rapid engine speed decrease, may contribute to fuel economy.

The inventors herein have recognized the above-mentioned issues and have developed a method for improving transmission shifting, comprising: increasing a field current of an alternator while maintaining or reducing alternator load applied to an engine via a controller in response to a request to upshift a transmission.

By increasing an alternator field current while maintaining or reducing alternator load that is applied to an engine, it may be possible to improve transmission shifting. In particular, the alternator field current may be increased so that the alternator may be prepared to apply a large load to the engine, thereby reducing engine speed to a speed that is a function of wheel speed and a new gear that is about to be engaged. At the same time, the load that is applied to the engine is not increased via the increased field current so that engine speed is not reduced while the off-going clutch may still be engaged. Thus, at the onset of an upshift, engine speed is not reduced early so that vehicle speed may be maintained, yet the alternator is being prepared to have capacity to apply a large load to the engine once the off-going clutch is released or nearly released. Such control may not be available with only alternator field control since increasing the alternator's field current may lead to higher alternator torque.

The present description may provide several advantages. In particular, the approach may improve transmission gear shifting. Further, the approach may control alternator load output independently from the control of the alternator field so that the mechanical load that is applied to the engine may be controlled independently from the field, thereby allowing the alternator's field to develop without changing the mechanical load that is applied to the engine. Further still, the approach may control alternator electrical current output independently from the control of the alternator field so that the electrical energy that is applied to the vehicle electric power consumers may be controlled independently from the field during a transmission gear shift.

DETAILED DESCRIPTION

The present description is related to shifting a transmission and adjusting a load applied to the engine during the shift so that engine speed may closer match transmission input shaft speed. The engine may be an internal combustion engine as shown inFIG. 1. The internal combustion engine may be included in a driveline or powertrain of a vehicle as shown inFIG. 2. The vehicle may include an alternator as shown inFIG. 3. The transmission may be shifted and the alternator may be operated according to the sequence ofFIG. 4. A flowchart of a method for shifting a transmission and adjusting operation of an alternator is shown inFIG. 5.

Referring toFIG. 1, internal combustion engine10, comprising a plurality of cylinders, one cylinder of which is shown inFIG. 1, is controlled by electronic engine controller12. The controller12receives signals from the various sensors shown inFIGS. 1-3and employs the actuators shown inFIGS. 1-3to adjust engine and driveline operation based on the received signals and instructions stored in memory of controller12.

Engine10is comprised of cylinder head35and block33, which include combustion chamber30and cylinder walls32. Piston36is positioned therein and reciprocates via a connection to crankshaft40. Flywheel97and ring gear99are coupled to crankshaft40. Optional starter96(e.g., low voltage (operated with less than 30 volts) electric machine) includes pinion shaft98and pinion gear95. Pinion shaft98may selectively advance pinion gear95to engage ring gear99. Starter96may be directly mounted to the front of the engine or the rear of the engine. In some examples, starter96may selectively supply torque to crankshaft40via a belt or chain. In one example, starter96is in a base state when not engaged to the engine crankshaft.

Combustion chamber30is shown communicating with intake manifold44and exhaust manifold48via respective intake poppet valve52and exhaust poppet valve54. Each intake and exhaust valve may be operated by an intake camshaft51and an exhaust camshaft53. The position of intake camshaft51may be determined by intake camshaft sensor55. The position of exhaust camshaft53may be determined by exhaust camshaft sensor57. Intake valves may be held open or closed over an entire engine cycle as the engine rotates via deactivating intake valve actuator59, which may electrically, hydraulically, or mechanically operate intake valves. Alternatively, intake valves may be opened and closed during a cycle of the engine. Exhaust valves may be held open or closed over an entire engine cycle (e.g., two engine revolutions) as the engine rotates via deactivating exhaust valve actuator58, which may be electrically, hydraulically, or mechanically operate exhaust valves. Alternatively, exhaust valves may be opened and closed during a cycle of the engine.

Fuel injector66is shown positioned to inject fuel directly into cylinder30, which is known to those skilled in the art as direct injection. Fuel injector66delivers liquid fuel in proportion to the pulse width from controller12. Fuel is delivered to fuel injector66by a fuel system (not shown) including a fuel tank, fuel pump, and fuel rail (not shown). In one example, a high pressure, dual stage, fuel system may be used to generate higher fuel pressures.

In addition, intake manifold44is shown communicating with turbocharger compressor162and engine air intake42. In other examples, compressor162may be a supercharger compressor. Shaft161mechanically couples turbocharger turbine164to turbocharger compressor162. Alternatively, compressor162may be electrically powered. Optional electronic throttle62adjusts a position of throttle plate64to control air flow from compressor162to intake manifold44. Pressure in boost chamber45may be referred to a throttle inlet pressure since the inlet of throttle62is within boost chamber45. The throttle outlet is in intake manifold44. In some examples, throttle62and throttle plate64may be positioned between intake valve52and intake manifold44such that throttle62is a port throttle. Waste gate163may be adjusted via controller12to allow exhaust gases to selectively bypass turbine164to control the speed of compressor162. Air filter43cleans air entering engine air intake42.

During operation, each cylinder within engine10typically undergoes a four stroke cycle: the cycle includes the intake stroke, compression stroke, expansion stroke, and exhaust stroke. During the intake stroke, generally, the exhaust valve54closes and intake valve52opens. Air is introduced into combustion chamber30via intake manifold44, and piston36moves to the bottom of the cylinder so as to increase the volume within combustion chamber30. The position at which piston36is near the bottom of the cylinder and at the end of its stroke (e.g. when combustion chamber30is at its largest volume) is typically referred to by those of skill in the art as bottom dead center (BDC).

During the compression stroke, intake valve52and exhaust valve54are closed. Piston36moves toward the cylinder head so as to compress the air within combustion chamber30. The point at which piston36is at the end of its stroke and closest to the cylinder head (e.g. when combustion chamber30is at its smallest volume) is typically referred to by those of skill in the art as top dead center (TDC). In a process hereinafter referred to as injection, fuel is introduced into the combustion chamber. In a process hereinafter referred to as ignition, the injected fuel is ignited by known ignition means such as spark plug92, resulting in combustion.

FIG. 2is a block diagram of a vehicle225including a powertrain or driveline200. The powertrain ofFIG. 2includes engine10shown inFIG. 1. Powertrain200is shown including vehicle system controller255, engine controller12, electric machine controller252, transmission controller254, and brake controller250. In some examples, electric machine controller252may be included in engine controller12, or vehicle system controller255, or in alternator279. The controllers may communicate over controller area network (CAN)299. Each of the controllers may provide information to other controllers such as torque output limits (e.g., torque output of the device or component being controlled not to be exceeded), torque input limits (e.g., torque input of the device or component being controlled not to be exceeded), torque output of the device being controlled, sensor and actuator data, diagnostic information (e.g., information regarding a degraded transmission, information regarding a degraded engine, information regarding a degraded electric machine, information regarding degraded brakes). Further, the vehicle system controller255may provide commands to engine controller12, electric machine controller252, transmission controller254, and brake controller250to achieve driver input requests and other requests that are based on vehicle operating conditions.

For example, in response to a driver releasing an accelerator pedal and vehicle speed, vehicle system controller255may request a desired wheel torque or a wheel power level to provide a desired rate of vehicle deceleration. The desired wheel torque may be provided by vehicle system controller255requesting a braking torque from brake controller250.

In other examples, the partitioning of controlling powertrain devices may be partitioned differently than is shown inFIG. 2. For example, a single controller may take the place of vehicle system controller255, engine controller12, electric machine controller252, transmission controller254, and brake controller250. Alternatively, the vehicle system controller255and the engine controller12may be a single unit while the electric machine controller252, the transmission controller254, and the brake controller250are standalone controllers.

In this example, powertrain200may be powered by engine10. Engine10may be started with an engine starting system shown inFIG. 1. Engine output torque may be provided to three phase alternator279via belt232, and alternator279may supply electrical energy to electric energy storage device (e.g., battery)274. Alternator279may be coupled to crankshaft40or a camshaft (e.g.,51or53). The output voltage of alternator279may be adjusted via adjusting a speed of first alternator279, a field current supplied to first alternator279, and an electric output regulator via controller252.

An engine output torque may be transmitted to torque converter206. Torque converter206includes a turbine286to output torque to input shaft270. Transmission input shaft270mechanically couples torque converter206to automatic transmission208. Torque converter206also includes a torque converter bypass lock-up clutch212(TCC). Torque is directly transferred from impeller285to turbine286when TCC is locked. TCC is electrically operated by controller254. Alternatively, TCC may be hydraulically locked. In one example, the torque converter may be referred to as a component of the transmission.

When torque converter lock-up clutch212is fully disengaged, torque converter206transmits engine torque to automatic transmission208via fluid transfer between the torque converter turbine286and torque converter impeller285, thereby enabling torque multiplication. In contrast, when torque converter lock-up clutch212is fully engaged, the engine output torque is directly transferred via the torque converter clutch to an input shaft270of transmission208. Alternatively, the torque converter lock-up clutch212may be partially engaged, thereby enabling the amount of torque directly relayed to the transmission to be adjusted. The transmission controller254may be configured to adjust the amount of torque transmitted by torque converter212by adjusting the torque converter lock-up clutch in response to various engine operating conditions, or based on a driver-based engine operation request. Torque converter206also includes pump283that pressurizes fluid to operate gear clutches211. Pump283is driven via impeller285, which rotates at a same speed as engine10.

Automatic transmission208includes gear clutches (e.g., gears 1-10)211and forward clutch210. Automatic transmission208is a fixed step ratio transmission. The gear clutches211and the forward clutch210may be selectively engaged to change a ratio of an actual total number of turns of input shaft270to an actual total number of turns of wheels216. Gear clutches211may be engaged or disengaged via adjusting fluid supplied to the clutches via shift control solenoid valves209. Torque output from the automatic transmission208may also be relayed to wheels216to propel the vehicle via output shaft260. Specifically, automatic transmission208may transfer an input driving torque at the input shaft270responsive to a vehicle traveling condition before transmitting an output driving torque to the wheels216. Transmission controller254selectively activates or engages TCC212, gear clutches211, and forward clutch210. Transmission controller also selectively deactivates or disengages TCC212, gear clutches211, and forward clutch210. In some examples, automatic transmission208may be replace with a manual transmission.

A frictional force may be applied to wheels216by engaging friction wheel brakes218. In one example, friction wheel brakes218may be engaged in response to the human driver pressing his/her foot on a brake pedal (not shown) and/or in response to instructions within brake controller250. Further, brake controller250may apply brakes218in response to information and/or requests made by vehicle system controller255. In the same way, a frictional force may be reduced to wheels216by disengaging wheel brakes218in response to the driver releasing his/her foot from a brake pedal, brake controller instructions, and/or vehicle system controller instructions and/or information. For example, vehicle brakes may apply a frictional force to wheels216via controller250as part of an automated engine stopping procedure.

In response to a request to accelerate vehicle225, vehicle system controller may obtain a driver demand torque or power request from an accelerator pedal or other device. Vehicle system controller255then commands engine10in response to the driver demand torque. Vehicle system controller255requests the engine torque from engine controller12. If engine torque is less than a transmission input torque limit (e.g., a threshold value not to be exceeded), the torque is delivered to torque converter206, which then relays at least a fraction of the requested torque to transmission input shaft270. Transmission controller254selectively locks torque converter clutch212and engages gears via gear clutches211in response to shift schedules and TCC lockup schedules that may be based on input shaft torque and vehicle speed. In some conditions when it may be desired to charge electric energy storage device274, a charging torque (e.g., a negative alternator torque) may be requested while a non-zero driver demand torque is present. Vehicle system controller255may request increased engine torque to overcome the charging torque to meet the driver demand torque.

In response to a request to decelerate vehicle225and provide regenerative braking, vehicle system controller may provide a negative desired wheel torque based on vehicle speed and brake pedal position. Vehicle system controller255then commands friction brakes218(e.g., desired friction brake wheel torque).

Accordingly, torque control of the various powertrain components may be supervised by vehicle system controller255with local torque control for the engine10, transmission208, and brakes218provided via engine controller12, electric machine controller252, transmission controller254, and brake controller250.

As one example, an engine torque output may be controlled by adjusting a combination of spark timing, fuel pulse width, fuel pulse timing, and/or air charge, by controlling throttle opening and/or valve timing, valve lift and boost for turbo- or super-charged engines. In the case of a diesel engine, controller12may control the engine torque output by controlling a combination of fuel pulse width, fuel pulse timing, and air charge. In all cases, engine control may be performed on a cylinder-by-cylinder basis to control the engine torque output.

Electric machine controller252may control torque output and electrical energy production from alternator279by adjusting current flowing to and from field and/or armature windings as described in greater detail in the description ofFIG. 3. Electrical output from alternator279may be provided in a stationary mode where the transmission is in park or neutral. Additionally, electrical output from the alternator279may be provided in a non-stationary mode where the vehicle is traveling on a road.

Transmission controller254receives transmission input shaft position via position sensor271. Transmission controller254may convert transmission input shaft position into input shaft speed via differentiating a signal from position sensor271or counting a number of known angular distance pulses over a predetermined time interval. Transmission controller254may receive transmission output shaft torque from torque sensor272. Alternatively, sensor272may be a position sensor or torque and position sensors. If sensor272is a position sensor, controller254may count shaft position pulses over a predetermined time interval to determine transmission output shaft velocity. Transmission controller254may also differentiate transmission output shaft velocity to determine transmission output shaft acceleration. Transmission controller254, engine controller12, and vehicle system controller255, may also receive addition transmission information from sensors277, which may include but are not limited to pump output line pressure sensors, transmission hydraulic pressure sensors (e.g., gear clutch fluid pressure sensors), alternator temperature sensors, and BISG temperature sensors, and ambient temperature sensors.

Brake controller250receives wheel speed information via wheel speed sensor223and braking requests from vehicle system controller255. Brake controller250may also receive brake pedal position information from brake pedal sensor154shown inFIG. 1directly or over CAN299. Brake controller250may provide braking responsive to a wheel torque command from vehicle system controller255. Brake controller250may also provide anti-skid and vehicle stability braking to improve vehicle braking and stability. As such, brake controller250may provide a wheel torque limit (e.g., a threshold negative wheel torque not to be exceeded) to the vehicle system controller255so that negative ISG torque does not cause the wheel torque limit to be exceeded. For example, if controller250issues a negative wheel torque limit of 50 N-m, ISG torque is adjusted to provide less than 50 N-m (e.g., 49 N-m) of negative torque at the wheels, including accounting for transmission gearing.

Referring now toFIG. 3, a detailed schematic of alternator279is shown. Alternator279is shown electrically coupled to a positive side355of electric energy storage device374and vehicle electrical consumers (e.g., lights, infotainment system, starter motor, etc.)310via conductor350. Alternator279is shown electrically coupled to a negative side356of electric energy storage device274and vehicle electrical consumers (e.g., lights, infotainment system, starter motor, etc.)310via conductor351. Conductor351is shown electrically coupled to ground potential306.

Alternator279includes a field winding303that is wound to a rotor305and three armature coils331-333that are wound to a stator330. Armature coils331-333are directly coupled together at node334and each of these coils provides one of three-phase electrical output of alternator279. Alternator279also includes an alternator field current control field effect transistor (FET)320and electrical output regulator section360. Electrical output regulator section360also provides a rectification function to provide direct current to electric energy storage device374. FET includes a drain (D), gate (G), and source (S). The drain is electrically coupled to conductor350. The gate is electrically coupled to controller252, and the source is electrically coupled to alternator field winding303. Electrical output regulator section360includes the transistors312-317. The transistors312-317are shown as bipolar transistors, but FETs or other known transistors may take the place of transistors312-317. Each of the transistors312-317includes a base370, emitter371, and collector372. Conductor380electrically couples emitter371of transistor312to the collector372of transistor315. Similarly, conductor381electrically couples transistor313to transistor316, and conductor382electrically couples transistor314to transistor317. Conductor385electrically couples one side of coil332to conductor380and the other side of coil332is electrically coupled to node334. Conductor387electrically couples one side of coil331to conductor382and the other side of coil331is electrically coupled to node334. Conductor386electrically couples one side of coil333to conductor381and the other side of coil333is electrically coupled to node334.

Controller252may adjust current supplied to field winding303via supplying a signal to field effect transistor (FET)320. Current flow through field winding303may be increased to increase electrical output of alternator279at electrical output regulator section360. Current flow through field winding303may be decreased to decrease electrical output of alternator279at electrical output regulator section360.

Controller252may also provide pulse width modulated signals to transistors312-317of the electrical output regulator section360. Output voltage and current of alternator279may be adjusted via adjusting the pulse widths of signals supplied to transistors312-317. For example, the output current from alternator279may be reduced via supplying a shorter duration pulse width signal (e.g., shorter transistor on or closed time) to the base of transistors312-317. Conversely, the output current from the alternator may be increased via supplying a longer duration pulse width signal (e.g., longer transistor on or closed time) to the base of transistors312-317. Controller supplies pulse width modulated control signals to transistors312-317at a frequency that is synchronous with the rotational frequency of rotor305.

All electrical output of alternator279to electric energy storage device274and vehicle electric consumers310may be ceased via opening all of transistors312-317. When all transistors312-317are in an open state, the mechanical load that alternator279applies to engine10is reduced to a low value. In a full load mode, transistors312-314may be open (e.g., deactivated) while transistors315-317are closed (e.g., activated) to generate maximum load applied by the alternator to the engine and no electrical output to electric energy storage device274and vehicle electric consumers310. Rather, electrical current is circulated through coils331-333in the full load mode. The full load mode may be enabled during transmission gear shifting to reduce engine speed during an upshift.

Thus, the system ofFIGS. 1-3provides for a system for shifting a transmission, comprising: an engine; an alternator coupled to the engine; a transmission coupled to the engine; and a controller including executable instructions stored in non-transitory memory to increase a field current of the alternator while maintaining or reducing alternator load applied to the engine in response to a request to upshift a transmission. The system further comprises additional instructions to decrease the field current in response to completing a transmission upshift generated via the request to upshift the transmission. The system further comprises additional instructions to maintain or decrease alternator electrical output supplied to vehicle power consumers external to the alternator in response to the request to upshift the transmission. The system further comprises further instructions to adjust a pulse width supplied to an output regulator of the alternator in response to the request to upshift the transmission. The system includes where adjusting the pulse width includes decreasing the pulse width in response to the request to upshift the transmission. The system further comprises additional instructions to increase an alternator load applied to the engine via adjusting a three phase regulator in response to releasing an off-going clutch.

Referring now toFIG. 4, a prophetic example sequence showing alternator operation during a transmission upshift is presented. The plots are time aligned and occur at a same time. The sequence ofFIG. 4may be generated via the system ofFIGS. 1-3in cooperation with the method ofFIG. 4. The vertical lines at time t0-t4represent times of interest in the sequence.

The first plot from the top ofFIG. 4is a plot of a transmission gear upshift (e.g., a request to shift from first gear to second gear) versus time. The vertical axis represents the state of the transmission gear upshift request. An upshift is requested when trace402is at a higher level near the vertical axis arrow. An upshift is not requested when trace402is at a lower level near the horizontal axis. The upshift may be in progress while the transmission upshift is being requested. In other words, the transmission upshift request may remain asserted until the requested upshift is complete. The horizontal axis represents time and time increase from the left side of the plot to the right side of the plot. Trace402represents the transmission upshift request.

The second plot from the top ofFIG. 4is a plot of alternator field current versus time. The vertical axis represents alternator field current and alternator field current increases in the direction of the vertical axis arrow. The horizontal axis represents time and time increases from the left side of the figure to the right side of the figure. Trace404represents alternator field current.

The third plot from the top ofFIG. 4is a plot of duty cycle of a signal that is applied to a transistor (e.g.,315) of the alternator's electrical output regulator section360via the controller252(each of transistors312-317may receive a signal with such a representative duty cycle). The vertical axis represents the duty cycle of the signal that is applied to the transistor of the alternator's electrical output regulator section360. The value of the duty cycle increases in the direction of the vertical axis arrow. The horizontal axis represents time and time increases from the left side of the figure to the right side of the figure. Trace406represents the duty cycle value of the signal that is applied to of the alternator's electrical output regulator section360.

The fourth plot from the top ofFIG. 4is a plot of torque that the alternator applies to the engine versus time. The vertical axis represents alternator torque and the magnitude of the alternator torque increases in the direction of the vertical axis. The alternator torque is indicated as a negative torque since is consumes engine torque. The horizontal axis represents time and time increases from the left side of the figure to the right side of the figure. Trace408represents the torque that the alternator applies to the engine.

The fifth plot from the top ofFIG. 4is a plot of engine torque versus time. The vertical axis represents engine torque and engine torque increases in the direction of the vertical axis arrow. The horizontal axis represents time and time increases from the left side of the figure to the right side of the figure. Trace310represents engine torque delivered to the engine crankshaft and trace312represents net engine torque provided to a torque converter or transmission input shaft (e.g., engine torque minus alternator torque).

At time t0, the engine is running (e.g., combusting fuel and rotating) (not shown) and the transmission is engaged in a first lower gear (not shown). The alternator field current is at a lower level that provides a desired voltage at the alternator output and the alternator supplies electrical power to a battery and vehicle electrical consumers (not shown). The alternator electrical output regulator section360duty cycle is at a higher level and the alternator torque that is applied to the engine is at a lower level. The engine torque is at a higher level and the net engine torque is slightly below the engine torque. Such conditions may be present when the engine is accelerating the vehicle just prior to shifting the transmission.

At time t1, a transmission gear upshift is requested and the alternator field current is increased so that the alternator may eventually apply a higher load torque to the engine later during the upshift. The slowly changeable field current begins to be adjusted to a maximum limit of alternator power absorbed at the pulley. The alternator electrical output regulator section duty cycle is decreased so that electrical output of the alternator may be maintained or decreased while the field current is increasing. Further, reducing the alternator electrical output regulator section duty cycle reduces the mechanical load torque that the alternator applies to the engine. The engine torque is reduced via adjusting an engine torque actuator (e.g., throttle, spark timing, cam timing, etc.) so that the net engine torque is not changed by reducing the alternator torque via the alternator electrical output regulator section. Between time t1and time t2, the off-going clutch begins to be released (not shown).

There are essentially two methods of modulating alternator output: 1. field current which may be changed slowly over many hundreds of milliseconds; and 2. synchronous control of rectifying transistors which changes the output quickly. Slow acting field control may be more electrically efficient than output control so the alternator may predominately be operated in filed control.

At time t2, the off-going clutch (e.g., the clutch that applies the lower transmission gear) is nearly fully released (not shown) and the duty cycle of the transistor is increased to indicate that transistor315is turned on. Transistors316and317are also turned on (not shown) and transistors312-314are turned off (not shown). Transistors315-317may be turned on at a 100 percent duty cycle to apply full load of the alternator to the engine. The alternator load increases in magnitude in response to the alternator electrical output regulator section adjustment. The net engine torque is reduced by the amount of torque that the alternator applies to the engine, thereby reducing the speed of the engine (not shown). The on-coming clutch (e.g., the clutch that is engaging the higher gear) may begin to engage at time t2.

This transfers the energy from the slowing the engine into the alternator. Alternatively, one could dump this energy into a storage device such as a battery. Typically, a 12-volt battery system would hit its limit of energy uptake during this period, which may send the system to an undesirable voltage of 18 or 19 volts. Therefore, the engine's energy is reduced via alternator heating rather than attempting to store it in the battery.

At time t3, the on-coming clutch is fully engaged so the alternator torque that is applied to the engine is reduced via closing transistors317-317(e.g., 0% duty cycle), thereby increasing the net engine torque that is delivered to the torque converter or the transmission input shaft. The alternator field current is reduced since full alternator mechanical load is no longer needed for the shift and the duty cycle of the signal that is applied to the transistor (e.g.,315) of the alternator's electrical output regulator section begins to increase so that the alternator may supply power to the battery and vehicle electric power consumers.

Between time t3and time t4, the transmission upshift continues with the on-coming clutch's torque capacity being increased (not shown) and the alternator field current being reduced. The duty cycle of the signal that is applied to the transistor of the alternator's electrical output regulator section continues to increase, thereby increasing alternator electrical output power to the battery and the vehicle electrical power consumers. The alternator torque increases as the duty cycle is increased and the engine torque is increased so that the net engine torque output is equal to the driver demand torque. The upshift completes at time t4and the alternator field current and output section are adjusted to provide the requested power to the battery and the vehicle electric power consumers.

In this way, the alternator field current and the electrical output regulator of the alternator may be simultaneously adjusted to provide changes in net engine torque that may smooth an upshift. Further, adjustments to the field current and the electrical output regulator may be coordinated with opening of the off-going clutch and closing of the on-coming clutch.

Referring now toFIG. 5, a method for upshifting a transmission and controlling an alternator during the upshift is shown. The method ofFIG. 5may provide the sequence shown inFIG. 4in conjunction with the system ofFIGS. 1-3. Further, at least portions of the method ofFIG. 5may be incorporated into a controller as executable instructions stored in non-transitory memory, while other portions of the method may be actions performed in the physical world via the system.

At502, method500judges if a transmission upshift is requested. A transmission upshift may be requested when vehicle operating conditions meeting conditions of a shift schedule that is stored in controller memory. For example, if the vehicle is accelerating and if it exceeds a threshold speed while the accelerator pedal is applied more than a threshold amount, a transmission upshift from a lower gear (e.g., 1stgear) to a higher gear (2ndgear) may be requested. If method500judges that a transmission upshift is requested, the answer is yes and method500proceeds to504. Otherwise, the answer is no and method500proceeds to520.

At520, method500adjusts the alternator's field current as a function of a desired alternator output voltage. In addition, the duty cycle of the alternator's electrical output regulator section360is adjusted to supply the alternators maximum output for the present amount of alternator field current. This allows the field current to be the sole regulator over alternator electrical output. Method500proceeds to exit.

At504, method500ramps off (e.g., reduces) the alternator's electrical output to the vehicle's battery and electric power consumers. The alternator's electrical output may be ramped off by adjusting (e.g., lowering) a duty cycle supplied to transistors312-317. The transistor duty cycle may be adjusted while increasing the amount of field current to the maximum field current such that the torque that the alternator applies to the engine is reduced. In addition, the off-going clutch (e.g., the clutch that operates the engaged lower gear during the upshift) may begin to be released. Method500proceeds to506.

At506, method500ramps down (e.g., reduces) engine torque at the rate that alternator torque applied to the engine is reduced so that the net engine torque is equal to the driver demand torque. The engine torque may be reduced via closing a throttle, retarding spark timing, or adjusting cam timing. In this way, the input torque to the transmission is maintained so that a driveline torque disturbance may not be generated. Method500proceeds to508.

At508, method fully opens transistors312-314and fully closes transistors315-317so that coils331-333are connected through transistors315-317. In one example, the transistors may be operated in this way in response to the off-going clutch being fully released or being nearly fully released. In this way, alternator's electrical output to the battery and vehicle electrical consumers is reduced to zero and the alternator mechanical load applied to the engine is a maximum, noting that field current may be at a maximum. However, it should be noted that field current need not be adjusted to a maximum level. Rather, the amount of field current may be a function of how much torque is desired to be applied to the engine via the alternator. The alternator's armature coils may be shorted together in this way just before or just after the off-going clutch is fully released. Method500proceeds to510.

At510, method500applies the on-coming clutch to engage the higher gear during the upshift. The on-coming clutch is commanded to fully close. Transistors315-317are commanded open to reduce the mechanical load that is applied by the alternator to the engine when the on-coming clutch is being closed or when the on-coming clutch is fully closed. Method500proceeds to512

At512, method500ramps on (e.g., increases) the alternator's electrical output to the vehicle's battery and electric power consumers. The alternator's electrical output may be ramped on by adjusting (e.g., increasing) a duty cycle supplied to transistors312-317. The transistor duty cycle may be adjusted while decreasing the amount of field current to provide a desired alternator output voltage. Method500proceeds to514.

At514, method500ramps up (e.g., increases) engine torque at the rate that alternator torque applied to the engine is increased so that the net engine torque is equal to the driver demand torque. The engine torque may be increased via adjusting an engine torque actuator (e.g., throttle, spark, camshaft, etc.). In this way, the input torque to the transmission is maintained during the upshift so that a driveline torque disturbance may not be generated. Method500proceeds to exit.

Thus, alternator field current may be adjusted while adjusting output of an electrical output regulator to change torque applied to the engine from zero to near full alternator torque in a time that is less than it takes for the alternator's field to fully develop. As such, the alternator's output torque control may be more responsive during a transmission gear shift.

The method ofFIG. 5provides for a method for improving transmission shifting, comprising: increasing a field current of an alternator while maintaining or reducing alternator load applied to an engine via a controller in response to a request to upshift a transmission. The method further comprises adjusting the field current responsive to an electrical load applied to the alternator when a transmission is not being shifted. The method includes where the alternator is a three phase electric machine. The method includes where the alternator includes a rectification circuit that supplied direct current to an electric energy storage device. The method further comprises rotating an armature of the alternator via an engine. The method includes where the field current is increased via adjusting output of a transistor that is electrically coupled to a field coil of the alternator. The method further comprises supplying electrical power from the alternator to ancillary vehicle electrical loads. The method further comprises increasing the alternator load applied to the engine in response to releasing an off-going clutch.

The method ofFIG. 5also provides for a method for improving transmission shifting, comprising: increasing a field current of an alternator while maintaining or decreasing alternator electrical output supplied to vehicle power consumers external to the alternator via a controller in response to a request to upshift a transmission. The method includes where the electrical output supplied to the vehicle power consumers is adjusted via an alternator output regulator. The method further comprises adjusting pulse width modulation of the alternator output regulator to maintain or decrease alternator electrical output supplied to vehicle power consumers external to the alternator. The method further comprises increasing alternator electrical output supplied to vehicle power consumers external to the alternator in response to completion of a transmission upshift. The method further comprises further adjusting the field current responsive to an electrical load applied to the alternator when a transmission is not being shifted. The method further comprises decreasing the field current in response to completing an upshift generated via the request to upshift the transmission.

In another representation, the method ofFIG. 5provides for a method for improving transmission shifting, comprising: adjusting current flow into an alternator via a controller and electric power output of the alternator via the controller and an output regulation circuit in response to a request to upshift a transmission. The method further comprises shorting coils of the alternator together in response to the request to upshift the transmission. The method includes where the coils are shorted together via transistors. The method further comprises controlling a mechanical load applied to via the alternator to an engine.

Note that the example control and estimation routines included herein can be used with various engine and/or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and may be carried out by the control system including the controller in combination with the various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. Further, at least a portion of the described actions, 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 actions may also transform the operating state of one or more sensors or actuators in the physical world when the described actions are carried out by executing the instructions in a system including the various engine hardware components in combination with one or more controllers.