METHOD AND SYSTEM FOR HIGH-VOLTAGE LOAD TRANSFERRING

Abstract

A method for operating a hybrid vehicle, which includes a high-voltage and a low-voltage bus, is described. In one example, the method involves lowering a threshold for high-voltage power consumption so that power consumers on the high-voltage bus can be identified as loads that can be switched off as part of a load shedding process. The high-voltage power consumption threshold can be based on the amount of electrical power that can be supplied by an internal combustion engine and an electric motor.

Description

field of technology

[0001] This description relates to a method and a system for mediating loads of a high-voltage electric power bus for a hybrid vehicle. The methods and systems can be advantageous when the engine torque is limited. General state of the art

[0002] A hybrid vehicle can include a high-voltage bus and a low-voltage bus. The low-voltage bus can be electrically connected to a low-voltage battery (e.g., 12 VDC). The low-voltage bus can transfer power between low-voltage charging devices, low-voltage storage devices, and low-voltage consumers (e.g., vehicle instruments, lighting, infotainment systems, etc.). The high-voltage bus can be electrically connected to a traction battery (e.g., > 400 VDC). The high-voltage bus can transfer power between the traction battery, the climate control system, a power distribution system for supplying electrical power to external devices, and an electric motor that can provide propulsion.The high-voltage bus can also be electrically coupled to the low-voltage bus via a power converter, allowing electrical energy to be transferred from the high-voltage bus to the low-voltage bus. However, there may be times when a motor and / or the electric machine does not have the capacity to supply electrical power to all power consumers.

[0003] It is understood that the foregoing background is provided to offer some context for the systems and methods described in the detailed description. It is not intended to identify in the background any important 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 overcome any of the disadvantages mentioned above or in any part of this disclosure. Brief description

[0004] A hybrid vehicle can include a high-voltage bus and a low-voltage bus. Electrical power can be transferred between the high-voltage and low-voltage buses via a power converter. During certain vehicle operating conditions, the engine and electric machine may lack the power output capacity to meet all electrical power requirements. In particular, engine power may be limited due to engine knock and / or pre-ignition at lower engine speeds. Consequently, if the vehicle cannot meet its electrical power requirements solely through the engine and electric machine, electrical power may be supplied to at least some power consumers via the high-voltage battery.However, if the high-voltage battery state of charge (SOC) falls below a threshold SOC, this can lead to impairment of the high-voltage battery and / or electrical power consumers may not receive their requested electrical power.

[0005] The inventors of the present invention have recognized the aforementioned problems and have developed a method for operating a vehicle which comprises: shedding electrical loads of a high-voltage bus in response to the fact that the electrical loads of the high-voltage bus exceed the electrical power generation capacity of a motor and an electric machine for motor speeds below a threshold speed.

[0006] By disconnecting or throttling high-voltage electrical loads that are electrically coupled to a high-voltage bus, it may be possible to achieve the technical result of inhibiting the reduction of the battery state of charge when large high-voltage loads are applied to a high-voltage bus and an internal combustion engine and an electric machine have insufficient capacity to supply enough electrical power to meet the needs of the large high-voltage loads.

[0007] The present description can offer several advantages. In particular, the approach can reduce the possibility of degradation of the high-voltage battery. Furthermore, the approach can enable charging of a high-voltage battery when its state of charge (SOC) is low and other high-voltage loads are demanding high-voltage power. Additionally, the approach evaluates the discharge of the high-voltage battery over several time intervals to increase confidence in whether or not setting a high-voltage load threshold will be beneficial.

[0008] The aforementioned advantages, as well as other advantages and features of the present description, will become readily apparent from the following detailed description, whether considered on its own or in conjunction with the accompanying drawings. Brief description of the drawings Fig. Figure 1 shows a schematic representation of an internal combustion engine; Fig. Figure 2 shows a schematic representation of an exemplary power transmission or drivetrain of a vehicle, including the components shown in Fig. 1 internal combustion engine shown; Fig. Figure 3 shows an example of a proportional / integral control for the in Fig. 3 drivetrain shown; and Fig. Figure 4 shows a flowchart of an exemplary procedure for the transmission of electrical power during selected vehicle operating conditions. Detailed description

[0009] This description concerns the control of the power distribution of a high-voltage bus and the control of the state of charge (SOC) of a high-voltage battery during operating conditions where the SOC of a high-voltage battery is low and a motor and / or electric machine does not have the capacity to supply the total amount of electrical power consumed by electrical loads. The vehicle may be a hybrid vehicle that includes an internal combustion engine, as in Fig. 1 shown. The internal combustion engine can be part of a hybrid powertrain, as shown in Fig. 2 shown. The power flow in the hybrid vehicle can be controlled via a proportional / integral (PI) controller of the type shown in Fig. Figure 3 is shown. The vehicle can be removed according to the procedure of Fig. 4 can be operated.

[0010] With reference to Fig. 1 is an internal combustion engine 10 comprising a plurality of cylinders, one of which is in Fig. As shown in Figure 1, the engine 10 is controlled by an electronic engine control unit 12. The engine 10 consists of a cylinder head 35 and a cylinder block 33, which include a combustion chamber 30 and cylinder walls 32. A piston 36 is positioned within the cylinder and moves back and forth via a connection to a crankshaft 40. A flywheel 97 and a ring gear 99 are coupled to the crankshaft 40. A starter 96 (e.g., a low-voltage electric motor (operated at less than 20 volts)) includes a pinion shaft 98 and a pinion gear 95. The pinion shaft 98 can selectively drive the pinion gear 95 so that it engages the ring gear 99. The starter 96 can be mounted directly on the front or rear of the internal combustion engine. In some examples, the starter 96 can selectively supply torque to the crankshaft 40 via a chain.In one example, the starter motor 96 is in a basic state when it is not engaged with the engine crankshaft.

[0011] According to the illustration, the combustion chamber 30 communicates with an intake manifold 44 and an exhaust manifold 48 via an intake control valve 52 and an exhaust control valve 54, respectively. Each intake and exhaust valve can be actuated by an intake cam 51 and an exhaust cam 53. The position of the intake cam 51 can be determined by an intake cam sensor 55. The position of the exhaust cam 53 can be determined by an exhaust cam sensor 57. The stroke volume and / or phase or position of the intake valve 52 can be adjusted relative to a position of the crankshaft 40 via a valve adjusting device 59. The stroke volume and / or phase or position of the exhaust valve 54 can be adjusted relative to a position of the crankshaft 40 via a valve adjusting device 58. The valve adjusting devices 58 and 59 can be electromechanical, hydraulic, or mechanical.

[0012] The engine 10 includes a crankcase 39 in which the crankshaft 40 is housed. An oil pan 37 can form a lower boundary of the crankcase 39, and the engine block 33 and the piston 36 can form an upper boundary of the crankcase 39. The crankcase 39 can include a crankcase ventilation valve (not shown) that can vent gases via the intake manifold 44 into the combustion chamber 30. The temperature of the oil in the crankcase 39 can be detected by a temperature sensor 38.

[0013] A fuel injection device 66 is positioned, as shown, to inject fuel directly into the cylinder 31, a process known to those skilled in the art as direct injection. The fuel injection device 66 delivers liquid fuel proportionally to the pulse width from the controller 12. The fuel is supplied to the fuel injection device 66 by a fuel system (not shown) comprising a fuel tank, a fuel pump, and a fuel distributor (not shown). In one example, a two-stage high-pressure fuel system can be used to generate higher fuel pressures.

[0014] Additionally, the intake manifold 44 communicates with a turbocharger compressor 162 and an engine air inlet 42, as shown in the illustration. In other examples, the compressor 162 may be a supercharger. A shaft 161 mechanically couples a turbocharger turbine wheel 164 to the turbocharger compressor 162. An optional electronic throttle 62 sets the position of a throttle valve 64 to control airflow from the compressor 162 to the intake manifold 44. The pressure in a charging chamber 45 can be referred to as the throttle inlet pressure, since the inlet of the throttle 62 is located in the charging chamber 45. The throttle outlet is located in the intake manifold 44. In some examples, the throttle 62 and the throttle valve 64 may be positioned between the intake valve 52 and the intake manifold 44 such that the throttle 62 acts as an intake port throttle.A compressor return valve 47 can be selectively adjusted to a variety of positions between fully open and fully closed. A wastegate 163 can be adjusted via the control 12 to allow exhaust gases to selectively bypass the turbine wheel 164 in order to control the speed of the compressor 162. An air filter 43 cleans the air entering the engine air intake 42.

[0015] A distributorless ignition system 88 provides a spark to the combustion chamber 30 via a spark plug 92 in response to the control unit 12. According to the diagram, a wideband lambda sensor (Universal Exhaust Gas Oxygen sensor - UEGO sensor) 126 is coupled to the exhaust manifold 48 upstream of a catalytic converter 70. Alternatively, the UEGO sensor 126 can be replaced by a binary lambda sensor.

[0016] In one example, catalyst 70 can contain multiple catalyst honeycomb structures. In another example, multiple emission control devices, each with multiple honeycomb structures, can be used. In another example, catalyst 70 can be a three-way catalyst.

[0017] Control 12 is in Fig. Figure 1 shows a conventional microcomputer comprising: a microprocessor unit 102, input / output ports 104, a read-only memory 106 (e.g., non-transient memory), a random-access memory 108, a keep-alive memory 110, and a conventional data bus.According to the illustration, in addition to the signals discussed above, the control unit 12 receives various signals from sensors coupled to the engine 10, including: a cylinder head temperature from a temperature sensor 112 coupled to the cylinder head 35; a position sensor 134 coupled to a driver-activated pedal 130 to detect a force applied by a human foot 132; a position sensor 154 coupled to a brake caliper control pedal 150 of the vehicle to detect a force applied by the foot 152; a manifold pressure (MAP) measurement from a pressure sensor 122 coupled to the intake manifold 44; an engine position sensor 118 detecting the position of the crankshaft 40; and a measurement of the mass of air flowing into the engine from a sensor 120. and a measurement of a throttle valve position from a sensor 68.Air pressure can also be detected for processing by the controller 12 (sensor not shown). In a preferred aspect of the present description, the engine position sensor 118 produces a predetermined number of evenly spaced pulses with each revolution of the crankshaft, from which the engine speed (RPM) can be determined.

[0018] During operation, each cylinder within the engine 10 typically goes through a four-stroke cycle: the cycle includes the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. During the intake stroke, the exhaust valve 54 generally closes and the intake valve 52 opens. Air is drawn into the combustion chamber 30 via the intake manifold 44, and the piston 36 moves toward the bottom of the cylinder to increase the volume within the combustion chamber 30. The position at which the piston 36 is near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber 30 has reached its maximum volume) is typically referred to by those skilled in the art as bottom dead center (BDC).

[0019] During the compression stroke, the intake valve 52 and the exhaust valve 54 are closed. The piston 36 moves towards the cylinder head to compress the air within the combustion chamber 30. The point at which the piston 36 is closest to the cylinder head at the end of its stroke (e.g., when the combustion chamber 30 has its smallest volume) is commonly referred to by those skilled in the art as top dead center (TDC). In a process referred to herein as injection, fuel is introduced into the combustion chamber. In a process referred to below as ignition, the injected fuel is ignited by known ignition means, such as the spark plug 92, resulting in combustion.

[0020] During the power stroke, the expanding gases push the piston 36 back to bottom dead center (BDC). The crankshaft 40 converts the piston movement into a torque of the crankshaft. Finally, during the exhaust stroke, the exhaust valve 54 opens to release the burnt air-fuel mixture to the exhaust manifold 48, and the piston returns to top dead center (TDC). It should be noted that the above is shown only as an example and that the timing for the opening and / or closing of the intake and exhaust valves can vary, for example, to provide positive or negative valve overlap, late closing of the intake valve, or various other examples.

[0021] Fig. Figure 2 is a block diagram of a vehicle 225, which includes a powertrain or transmission 200. The powertrain of the Fig. 2 includes the one in Fig. The powertrain 200, as shown in Figure 1, includes a vehicle system controller 255, a motor controller 12, an electric machine controller 252, a transmission controller 254, an energy storage device controller 253, and a friction brake caliper controller 250. The controllers can communicate via a Controller Area Network (CAN) 299. Each of the controllers can provide information to other controllers, such as power output thresholds (e.g., a maximum power output of the controlled device or component), power input thresholds (e.g., a maximum power input of the controlled device or component), a power output of the controlled device, sensor and actuator data, and diagnostic information (e.g.,Information regarding a malfunctioning transmission, engine, electric machine, and friction brake calipers). Furthermore, the vehicle system control 255 can provide commands to the engine control 12, the electric machine control 252, the transmission control 254, and the brake caliper control 250 to fulfill driver input requests and other requirements based on vehicle operating conditions.

[0022] For example, in response to a driver releasing a driver-activated accelerator pedal or to the vehicle speed, the vehicle control unit 255 can request a desired wheel power or a desired wheel power level to provide a desired rate of vehicle deceleration. The requested desired wheel power can be provided by the vehicle control unit 255 requesting a first vehicle deceleration power from the electric machine control unit 252 and a second vehicle deceleration power from the motor control unit 12, with the first and second powers providing a desired vehicle deceleration power to the power transmission at the vehicle wheels 216. The vehicle control unit 255 can also request friction brake caliper power via the brake caliper control unit 250.Vehicle deceleration can be described as negative performance, as it slows down power transmission and wheel rotation. Positive performance can maintain or increase power transmission and wheel rotation.

[0023] The vehicle control unit 255 and / or the engine control unit 12 can also receive input from a human-machine interface 256 and traffic conditions (e.g., traffic light status, distance to objects, etc.) from sensors 257 (e.g., cameras, LiDAR, radar, etc.). For example, the human-machine interface 256 could be a touchscreen display panel. Alternatively, the human-machine interface 256 could be a key switch or another known type of human-machine interface. The human-machine interface 256 can receive requests from a user. For example, a user can request an engine stop or start via the human-machine interface 256. Furthermore, a user can override a prevention of wheel movement 216 when an external electrical power consumer 297 is connected to the vehicle 255.In addition, the human-machine interface 256 can display status messages and motor data that can be received by the controller 255.

[0024] In other examples, the distribution of control of the powertrain devices may be different than in Fig. Figure 2 shows this. For example, a single controller can replace the vehicle system controller 255, the motor controller 12, the electric machine controller 252, the transmission controller 254, and the brake caliper controller 250. Alternatively, the vehicle system controller 255 and the motor controller 12 can be a single unit, while the electric machine controller 252, the transmission controller 254, and the brake caliper controller 250 are separate controllers.

[0025] In this example, the drive train 200 can be powered by the motor 10 and an electric machine 240. In other examples, the motor 10 can be omitted. The motor 10 can be started with a motor starting system that is in Fig. As shown in Figure 1, the vehicle can be started via an integrated starter / generator BISG 219 or via the electric machine. The temperature of the BISG windings can be determined via a BISG winding temperature sensor 203. The electric machine 240 (e.g., a high-voltage electric machine (operated at more than 30 volts)) can also be referred to as an electric motor and / or generator. Furthermore, the power output of the motor 10 can be adjusted via a torque actuator 204, such as a fuel injection device, a throttle, etc.

[0026] The BISG 219 is mechanically coupled to the motor 10 via a chain 231 and can be described as an electric machine, electric motor, or generator. The BISG 219 can be connected to the crankshaft 40 or a camshaft (e.g., 51 or 53). Fig. 1) be coupled. The BISG 219 can be operated as an electric motor when electrical power is supplied to it via a low-voltage bus 273 and / or a low-voltage battery 280. The BISG 219 can be operated as a generator that supplies electrical power to the low-voltage battery 280 and / or the low-voltage bus 273. A power converter 281 (e.g., a bidirectional DC-DC converter) can transfer electrical energy from a high-voltage bus 274 to a low-voltage bus 273 or vice versa. The low-voltage battery 280 is electrically coupled directly to the low-voltage bus 273. The low-voltage bus 273 can consist of one or more electrical conductors. The electrical energy storage device 275 (e.g., a high-voltage battery or traction battery) is electrically coupled to the high-voltage bus 274.An electric heater 266 with a positive temperature coefficient (PTC) and an electrically driven climate control system (e.g., a heat pump) 267 are also electrically coupled to the high-voltage bus 274 and can receive electrical power via the high-voltage bus 274. The low-voltage battery 280 can selectively supply electrical energy to the starter motor 96 and / or the BISG 219.

[0027] Motor output power can be transmitted via a dual-mass flywheel 215 to a first or upstream side of a drivetrain release clutch 235. The release clutch 236 is hydraulically actuated, and the hydraulic pressure in the power transmission release clutch 236 (power transmission release clutch pressure) can be adjusted via an electrically operated valve 233. The downstream or second side 234 of the release clutch 236 is mechanically coupled to an input shaft 237 of the electric motor, as shown in the illustration.

[0028] The electric machine 240 can be operated to provide power to the drive train 200 or, in a regeneration mode, to convert drive train power into electrical energy, which is stored in the electrical energy storage device 275. The electric machine 240 communicates electrically with the energy storage device 275 via an inverter 279. The inverter 279 can convert direct current (DC) from the electrical energy storage device 275 into alternating current (AC) to operate the electric machine 240. Alternatively, the inverter 279 can convert AC from the electric machine 240 into DC for storage in the electrical energy storage device 275. The inverter 279 can be controlled via the electric machine's controller 252. The electric machine 240 has a higher output power capacity than the one described in [reference missing]. Fig. The electric machine 240 is driven directly by the drive train 200 or is directly driven by the drive train 200. There are no gears or chains to couple the electric machine 240 to the drive train 200. Rather, the electric machine 240 rotates at the same rate as the drive train 200. The electrical energy storage device 275 (e.g., a high-voltage battery or power source) can be a battery, a capacitor, or an inductor. The downstream side of the electric machine 240 is mechanically coupled to the impeller 285 of the torque converter 206 via a shaft 241. The upstream side of the electric machine 240 is mechanically coupled to the disengagement clutch 236.The electric machine 240 can provide positive or negative power to the drive train 200 by operating as an electric motor or generator, as directed by the control unit 252 of the electric machine.

[0029] The power converter 278 (e.g., an inverter) is electrically connected via a high-voltage bus 274 to the electrical energy storage device 275 and an electrical output socket 295. The power converter 278 can convert DC to AC to operate an external electrical load 297 (e.g., handheld devices, entertainment systems, lighting, pumps, etc.). The power converter 278 can convert electrical power from the low-voltage battery 280, electrical power from the electrical energy storage device 275, or electrical power from the electric machine 240 or the BISG 219 into electrical power that is delivered to the electrical output socket 295. The external electrical load 297 can be located outside the vehicle 225 or can be added to the vehicle 225.The external power consumer 297 can be electrically connected to the electrical output socket 295 via a power cable 296. An external power consumer sensor 298 can detect the presence or absence of an external power consumer 297. The external power consumer sensor 298 can physically detect the presence of the cable 296 via a switching input, or alternatively, the sensor 298 can be a current sensor and detect electrical current flow from the electrical output socket 295 to determine the presence or absence of an external power consumer 297.

[0030] The torque converter 206 includes a turbine wheel 286 to output power to an input shaft 270. The input shaft 270 mechanically couples the torque converter 206 to an automatic transmission 208. The torque converter 206 also includes a torque converter bypass lock-up clutch (TCC) 212. Power is transferred directly from the pump wheel 285 to the turbine wheel 286 when the TCC 212 is locked. The TCC 212 is electrically operated by the control unit 254. Alternatively, the TCC can be locked hydraulically. In this example, the torque converter 206 can be considered a component of the transmission.

[0031] When the torque converter lock-up clutch 212 is fully disengaged, the torque converter 206 transmits engine power to the automatic transmission 208 via a fluid transfer between the torque converter turbine wheel 286 and a torque converter pump wheel 285, thus enabling torque multiplication. Conversely, when the torque converter lock-up clutch 212 is fully engaged, the engine output power is transmitted directly to an input shaft 270 of the transmission 208 via the torque converter clutch. Alternatively, the torque converter lock-up clutch 212 can be partially engaged, allowing the amount of power delivered directly to the transmission to be adjusted.The transmission control unit 254 can be configured to adjust the amount of power transmitted through the torque converter lock-up clutch 212 by adjusting the torque converter lock-up clutch in response to different engine operating conditions or based on a driver-based engine operating request.

[0032] The torque converter 206 also includes a pump 283, which pressurizes fluid to operate the release clutch 236, a forward clutch 210, and gear clutches 211. The pump 283 is driven by the impeller 285, which rotates at the same speed as the electric motor 240.

[0033] The automatic transmission 208 includes the gear clutches 211 and the forward clutch 210 for selectively engaging and disengaging forward gears 213 (e.g., gears 1-10) and reverse gear 214. The automatic transmission 208 is a fixed-ratio transmission. Alternatively, the transmission 208 can be a continuously variable transmission (CVT) capable of simulating fixed-ratio transmissions. The gear clutches 211 and the forward clutch 210 can be selectively engaged to change the ratio of an actual total number of input shaft 270 rotations to an actual total number of wheel 216 rotations. The gear clutches 211 can be engaged or disengaged by adjusting the fluid supplied to the clutches via shift control solenoid valves 209.The power output from the automatic transmission 208 can also be transmitted to the wheels 216 to drive the vehicle via an output shaft 260. Specifically, the automatic transmission 208 can transmit input drive power at the input shaft 270 in response to a driving condition of the vehicle before transmitting output drive power to the wheels 216. The transmission control unit 254 selectively engages or engages the transmission control unit 212, the gear clutches 211, and the forward clutch 210. The transmission control unit also selectively disengages or disengages the transmission control unit 212, the gear clutches 211, and the forward clutch 210.

[0034] Furthermore, a frictional force can be applied to the wheels 216 by engaging friction brake calipers 218. For example, the friction wheel brake calipers 218 can be engaged in response to a human driver pressing their foot on a vehicle brake caliper control pedal (not shown) and / or in response to instructions within the brake caliper control 250. The brake caliper control 250 can also engage the friction brake calipers 218 in response to information and / or requests from the vehicle system control 255. Similarly, a frictional force on the wheels 216 can be reduced by disengaging the friction brake calipers 218 in response to the human driver removing their foot from a brake caliper pedal, in response to instructions from the brake caliper control, and / or vehicle system control instructions and / or information.

[0035] In response to a request to move the vehicle 225, the vehicle control unit can receive a driver-demand power request from a driver-demand pedal or other device. The vehicle control unit 255 then allocates a portion of the requested driver-demand power to the engine and the remainder to the electric machine or the BISG (Battery Energy Shift Gearbox). The vehicle control unit 255 requests the engine power from the engine control unit 12 and the electric machine power from the electric machine control unit 252. If the electric machine power plus the engine power is less than a transmission input power threshold (e.g., a non-exceeding power input threshold), the power is delivered to the torque converter 206, which then transmits at least a portion of the requested power to the transmission input shaft 270.The transmission control unit 254 selectively bypasses the torque converter clutch 212 and engages gears via the gear clutches 211 in response to shift patterns and TCC bypass patterns, which may be based on the input shaft power and vehicle speed. Under certain conditions, when it may be desirable to charge the electrical energy storage device 275, charging power (e.g., negative power from the electric machine) may be requested while the driver demand is non-zero. The vehicle system control unit 255 may request increased engine power to overcome the charging power requirement in order to meet the driver demand.

[0036] Accordingly, the power control of the various powertrain components can be monitored by the vehicle system control 255, with local power control for the motor 10, the transmission 208, the electric machine 240 and the friction brake calipers 218 being provided via the motor control 12, the electric machine control 252, the transmission control 254 and the brake caliper control 250.

[0037] As an example, engine power output can be controlled by adjusting a combination of ignition timing, fuel pulse width, fuel pulse timing, and / or air charge; by controlling throttle opening and / or valve timing, valve lift, and boost for turbocharged or supercharged engines. In the case of a diesel engine, the controller 12 can control the engine power output by controlling a combination of fuel pulse width, fuel pulse timing, and air charge. Engine speed reduction power, or negative engine power, can be provided by rotating the engine, with the engine generating power that is insufficient to turn the engine. Thus, the engine can be operated at low power during fuel combustion with one or more cylinders deactivated (e.g., by disabling the cylinders).(No fuel is burned) or, with all cylinders deactivated, the engine generates deceleration power while rotating. The amount of engine deceleration power can be adjusted by adjusting the engine valve timing. The engine valve timing can be adjusted to increase or decrease engine compression work. Furthermore, the engine valve timing can be adjusted to increase or decrease engine expansion work. In all cases, the engine timing can be adjusted cylinder by cylinder to control engine power output.

[0038] The control unit 252 of the electrical machine can control the power output and the generation of electrical energy from the electrical machine 240 by adjusting the current flowing to and from the field and / or armature windings of the electrical machine 240, as is known in the field.

[0039] The transmission control unit 254 receives a transmission input shaft position via a position sensor 271. The transmission control unit 254 can convert the transmission input shaft position into input shaft speed by differentiating a signal from the position sensor 271 or by counting a number of known angular distance pulses over a predetermined time interval. The transmission control unit 254 can receive the torque of the transmission output shaft from a torque sensor 272. Alternatively, the sensor 272 can be a position sensor or a torque and a position sensor. If the sensor 272 is a position sensor, the control unit 254 can count shaft position pulses over a predetermined time interval to determine the transmission output shaft speed.The transmission control unit 254, the engine control unit 12, and the vehicle system control unit 255 can also receive additional transmission information from sensors 277, which may include, among others, pressure sensors of the pump output line, hydraulic pressure sensors of the transmission (e.g., fluid pressure sensors of the transmission clutch), ISG temperature sensors and BISG temperatures, gearshift lever sensors, and ambient temperature sensors. The transmission control unit 254 can also receive a requested gear input from a gearshift lever 290 (e.g., a human-machine interface device). The gearshift selector lever 290 can include positions for gears 1-X (where X is a higher gear number), D (Drive), Neutral (N), and P (Park). The shift lever 293 of the gear selector lever 290 can be controlled by a solenoid actuator 291, which selectively prevents the shift lever 293 from moving from the park or neutral position into a reverse or forward gear position (e.g.(driving) is moved, or prevented from moving.

[0040] The brake caliper control unit 250 receives wheel speed information via a wheel speed sensor 221 and vehicle deceleration requests from the vehicle system control unit 255. The brake caliper control unit 250 can also receive vehicle brake caliper control pedal position information from the [unclear text]. Fig. The brake caliper application pedal sensor 154 shown in Figure 1 receives the signal directly or via CAN 299. The brake caliper control 250 can provide deceleration in response to a wheel power command from the vehicle system control 255. The brake caliper control 250 can also provide anti-lock braking and vehicle stability brake caliper activation to increase vehicle stability. Thus, the brake caliper control 250 can provide the vehicle system control 255 with a wheel power threshold (e.g., a non-exceedable threshold for negative wheel power) so that the negative ISG power does not cause the wheel power threshold to be exceeded. For example, if the brake caliper control 250 outputs a negative wheel torque threshold of 50 Nm, the power of the electric machine is adjusted so that less than 50 Nm (e.g.,49 Nm) negative torque is provided at the wheels, which includes compensating for the gear ratio.

[0041] The system of Fig. 1 and Fig. 2 provides a vehicle system comprising: an internal combustion engine; an electric machine; a traction battery; a high-voltage bus electrically coupling the electric machine and the traction battery; and a controller containing executable instructions stored in non-transient memory that cause the controller to lower a high-voltage load threshold in response to the traction battery's state of charge (SOC) depleting over a variety of time intervals. In a first example, the vehicle system further comprises additional executable instructions stored in non-transient memory that cause the controller to lower the high-voltage load threshold via a proportional / integral (PI) controller.In a second example, which may include the first example, the vehicle system specifies that the high-voltage load threshold is an output of the PI controller and that a minimum target traction battery state of charge (SOC) is an input to the PI controller. In a third example, which may include one or both of the first and second examples, the vehicle system specifies that the high-voltage load threshold is a power output that can be transferred over the high-voltage bus. In a fourth example, which may include one or more of the first three examples, the vehicle system specifies that the high-voltage load threshold is based on a maximum electrical load supported by the internal combustion engine and the electric motor.In a fifth example, which may include one or more of the first four examples, the vehicle system further includes the high-voltage load threshold being based on a low-voltage bus load and a buffer load. In a sixth example, which may include one or more of the first five examples, the vehicle system further includes additional executable instructions that cause the controller to throttle high-voltage power consumers electrically coupled to the high-voltage bus in response to the high-voltage load threshold (e.g., limiting the flow of electrical power to a device to less than a maximum rated power flow to the device).In a seventh example, which may include one or more of the first to sixth examples, the vehicle system further comprises a transmission coupled to the electric machine and additional executable instructions that cause the controller to lower the high-voltage load threshold while the transmission is engaged for driving.

[0042] With reference to Fig. Figure 3 shows a block diagram of an exemplary proportional / integral (PI) controller for high-voltage load switching based on a limitation of the engine torque. The PI controller 300 receives a minimum target high-voltage battery state of charge (SOC). The minimum target high-voltage battery SOC is the lowest SOC level at which the high-voltage battery is deliberately controlled to achieve the desired vehicle power and high-voltage battery energy. The minimum target high-voltage battery SOC is input to a junction 304, where the current high-voltage battery SOC (e.g., of the traction battery) is subtracted from the minimum target high-voltage battery SOC. The output of junction 304 is input to a proportional gain block 306 and an integral gain block 308.Proportional gain block 306 multiplies a value output by junction 304 by a real number. The real number can be a fixed value or its value can depend on operating conditions, such as battery temperature. Proportional gain block 306 feeds the result of the multiplication to junction 310. Integral gain block 308 numerically integrates the output of junction 304 and feeds the result of the numerical integration to junction 310. Junction 310 sums the output of proportional gain block 306 and the output of integral gain block 308. The output of junction 310 is a high-voltage load threshold (e.g., a maximum amount of power that the motor, electric machine, and / or battery can deliver under their current operating conditions).

[0043] Referring to Fig. Figure 4 shows a flowchart of a procedure for mediating electrical power from a hybrid vehicle during selected vehicle operating conditions. At least sections of the procedure 400 can be implemented as executable control instructions stored in non-transient memory. The procedure 400 can be used in conjunction with the system of Fig. 1 and Fig. 2. Additionally, parts of the procedure can be measures that are carried out in the real world to transform an operating state of an actuator or device.

[0044] In 402, the procedure determines vehicle operating conditions. The vehicle operating conditions can be determined or estimated using the various sensors described herein. The vehicle operating conditions may include, among others, a high-voltage battery state of charge (SOC), engine torque, engine speed, vehicle speed, high-voltage battery voltage, high-voltage battery current, low-voltage battery voltage, low-voltage battery current, catalyst temperature, driver-demand torque, engine temperature, ambient temperature, and ambient pressure. Procedure 400 transitions to 404.

[0045] In procedure 404, procedure 400 assesses whether selected conditions have been met to enable high-voltage load switching based on an engine torque constraint for a hybrid vehicle. In an example, selected conditions might include the vehicle speed being below a threshold speed, the internal combustion engine operating within a predetermined percentage of the maximum available engine torque for the current engine speed, the high-voltage battery state of charge (SOC) being discharged beyond a predetermined threshold, and the vehicle being in drive, park, or idle. If these conditions are met, the answer is yes, and procedure 400 proceeds to 406. Otherwise, the answer is no, and procedure 400 proceeds to the end.

[0046] In procedure 406, procedure 400 samples (e.g., measures and / or determines) the change in the high-voltage battery state of charge (SOC) over a variety of predetermined time intervals. For example, procedure 400 can monitor and track the change in the high-voltage battery SOC over the following time intervals: ten seconds, thirty seconds, sixty seconds, three hundred seconds, and twelve hundred seconds. Procedure 400 then proceeds to procedure 408.

[0047] In procedure 408, procedure 400 assesses whether the high-voltage battery state of charge (SOC) is discharging over predetermined time intervals. For example, procedure 400 can determine whether the high-voltage battery SOC is decreasing over a predetermined proportion or a number of predetermined time intervals. For instance, if procedure 400 assesses that the high-voltage battery SOC is discharging over time intervals of thirty, sixty, and three hundred seconds, it can assess whether the high-voltage battery SOC is discharging over predetermined time intervals. If procedure 400 assesses that the high-voltage battery SOC is discharging over the predetermined time intervals, the answer is yes, and procedure 400 proceeds to 410. Otherwise, the answer is no, and procedure 400 returns to 406.

[0048] In procedure 400, method 410 determines a maximum electrical load (e.g., a maximum amount of power) that can be supported without discharging the high-voltage battery. For example, the maximum amount of power that can be supported without discharging the high-voltage battery could be the amount of electrical power that can be generated by motor 10 and electric machine 240. The maximum amount of power can be expressed using the following equation: Totelec=Engpow(n,afr,temp,spk,camtime,bp,ambT) ⋅ηelec(nele,Tele) where Totelec is the total amount of electrical power that can be supplied by the motor and electric machine under current operating conditions, Engpow is a function that returns the motor power as a function of the motor speed n, the air-fuel ratio afr of the motor, the motor temperature t, the motor ignition spark spk, the motor cam control, the air pressure bp and the ambient air temperature ambT, η elec A function that returns the efficiency of the electric machine for converting mechanical power into electrical power, where nele is the speed of the electric machine and Tele is the temperature of the electric machine. Method 400 transitions to 412.

[0049] At 412, procedure 400 estimates the current low-voltage load of the low-voltage battery. In one example, procedure 400 estimates the low-voltage power consumption by multiplying a voltage of the low-voltage bus by a quantity of current flowing through the low-voltage bus. Alternatively, procedure 400 can query low-voltage load consumers, and the low-voltage load consumers can report their power consumption to procedure 400. Procedure 400 can then sum the power consumed by low-voltage load consumers to determine the low-voltage power consumption. Procedure 400 then proceeds to 414.

[0050] In step 414, procedure 400 subtracts the low-voltage power consumption quantity plus a predetermined buffer power quantity from the total amount of electrical power determined in step 410 to determine a high-voltage load threshold quantity (e.g., a power quantity that the motor, electric machine, and / or high-voltage battery can supply to the power consumers receiving electrical power via the high-voltage bus). Procedure 400 then proceeds to step 416.

[0051] Procedure 400 reduces high-voltage loads at 416, causing the high-voltage battery state of charge (SOC) to stop discharging. Procedure 400 can reduce high-voltage loads according to a predetermined schedule and based on the priority of the high-voltage loads. For example, Procedure 400 can reduce the climate control load before reducing the power supplied to low-voltage loads via the high-voltage bus. The high-voltage loads can be completely shut down, or the power supplied to the high-voltage loads can be gradually reduced until the high-voltage battery SOC stops discharging. The reduction of high-voltage loads can be stopped after the high-voltage battery SOC has finished discharging. Procedure 400 then transitions to 418.

[0052] In case 418, procedure 400 applies the one in Fig. Figure 3 uses PI control to reduce the power consumption of the high-voltage bus to a state where the high-voltage battery begins to charge from a charge generated by the motor and electric machine. Lowering the high-voltage battery load threshold reduces the power supplied to high-voltage power consumers. The flow of high-voltage power to these consumers can be further reduced by limiting the amount of electrical power supplied to them (e.g., by restricting the power supplied). For example, the amount of electrical power supplied to an electrically driven climate control system can be reduced from 4 kilowatts to 3.8 kilowatts.In some examples, high-voltage power supplied to high-voltage power consumers can be weighted according to the device type of the high-voltage power consumer. For example, high-voltage power supplied to the low-voltage bus via power transformer 281 can be weighted with a higher priority than high-voltage power supplied to a climate control system, so that a larger proportion of the power supplied to the low-voltage bus may be than a larger proportion of the power supplied to the climate control system. Alternatively, one or more of the high-voltage power consumers can be switched off (e.g., by shedding electrical loads) in response to an increase in the high-voltage bus load threshold to reduce their high-voltage power consumption.Once the total electrical load is low enough, charging of the high-voltage battery can begin, allowing the high-voltage battery state of charge (SOC) to be set to the minimum target SOC. Procedure 400 then transitions to 420.

[0053] At 420, procedure 400 assesses whether the high-voltage battery is at or above the minimum target high-voltage battery state of charge (SOC). If so, the answer is yes, and procedure 400 returns to 404. Otherwise, the answer is no, and procedure 400 returns to 418.

[0054] In this way, Method 400 can adjust the electrical power supplied to high-voltage loads in response to the electrical power capacity of the motor and electric machine, thus preventing the high-voltage battery state of charge (SOC) from being lowered more than desired. Additionally, Method 400 controls which loads are given priority.

[0055] Thus, the procedure of Fig. 4. A method for operating a vehicle is provided, comprising: shedding electrical loads from a high-voltage bus in response to the electrical loads of the high-voltage bus exceeding the electrical power-generating capacity of a motor and an electric machine for motor speeds below a threshold speed. In a first example, the method further comprises throttling electrical loads from the high-voltage bus in response to the electrical loads of the high-voltage bus exceeding the electrical power-generating capacity of the motor and the electric machine for motor speeds below the threshold speed. In a second example, which may include the first example, the method further comprises shedding the electrical loads from the high-voltage bus as a further response to a high-voltage battery state of charge (SOC) discharging over a plurality of different predetermined threshold periods.In a third example, which may include one or both of the first and second examples, the method further includes shedding the electrical loads of the high-voltage bus as a further response to a vehicle's internal combustion engine operating within a predetermined threshold of maximum available engine torque at a current engine speed. In a fourth example, which may include one or more of the first through third examples, the method includes shedding the electrical loads of the high-voltage bus as a further response to a vehicle's transmission being in park or neutral. In a fifth example, which may include one or more of the first through fourth examples, the method includes shedding the electrical loads of the high-voltage bus as a further response to a reduction in a high-voltage load threshold.In a sixth example, which may include one or more of the first to fifth examples, the procedure involves the high-voltage load being based on a low-voltage bus load and a buffer low-voltage bus load.

[0056] The procedure of Fig.Section 4 further provides a method for operating a vehicle that includes: lowering a high-voltage power consumption threshold in response to a high-voltage battery state of charge (SOC) being lower than a minimum target high-voltage battery SOC. In a first example, the method further includes lowering the high-voltage power consumption threshold in a further response to a combined charging capacity of an internal combustion engine and an electric machine being lower than the actual total electrical load of the vehicle. In a second example, which may include the first example, the method includes the total electrical load of the vehicle including the electrical load of a low-voltage bus.In a third example, which may include one or both of the first and second examples, the method involves the entire electrical load of the vehicle including the electrical load of a high-voltage bus. In a fourth example, which may include one or more of the first through third examples, the method involves the electrical load of the high-voltage bus including a power distribution system to supply electrical power outside the vehicle.

[0057] It should be noted that the exemplary control and estimation routines contained herein can be used with various internal combustion engine and / or vehicle system configurations. The control procedures and routines disclosed herein can be stored as executable instructions in non-transient memory and can be executed by the control system in conjunction with the various sensors, actuators, and other internal combustion engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Therefore, various illustrated actions, operations, and / or functions can be performed in the illustrated sequence or in parallel, or in some cases, omitted.Similarly, the processing sequence is not strictly necessary to achieve the features and advantages of the exemplary embodiments described herein, but is provided for the sake of simplification of illustration and description. One or more of the illustrated actions, processes, and / or functions can be performed repeatedly, depending on the specific strategy used. Furthermore, at least some of the described actions, processes, and / or functions can be graphically represented as code that is to be programmed into a non-transient memory of the computer-readable storage medium in the control system.Furthermore, the control actions can transform the operating state of one or more sensors or actuators in the real world when the described actions are carried out by executing the instructions in a system that includes the various motor hardware components in combination with one or more controllers.

[0058] This concludes the description. Upon reading it, a person skilled in the art would notice many changes and modifications without altering the essence and scope of the description. For example, I3, I4, I5, V6, V8, V10, and V12 internal combustion engines operating in natural gas, gasoline, diesel, or alternative fuel configurations could benefit from this description.

[0059] According to the present invention, a method for operating a vehicle includes: shedding electrical loads from a high-voltage bus in response to the fact that the electrical loads of the high-voltage bus exceed the electrical power generation capacity of a motor and an electric machine for motor speeds below a threshold speed.

[0060] In one aspect of the invention, the method involves throttling electrical loads of the high-voltage bus in response to the fact that the electrical loads of the high-voltage bus exceed the electrical power generation capacity of the motor and the electric machine for motor speeds below the threshold speed.

[0061] In one aspect of the invention, the method involves shedding the electrical loads of the high-voltage bus as a further response to a high-voltage battery SOC discharging over a multitude of predetermined threshold periods.

[0062] In one aspect of the invention, the method involves shedding the electrical loads of the high-voltage bus as a further reaction to the fact that an internal combustion engine of the vehicle is operated within a predetermined threshold of a maximum available engine torque at a current engine speed.

[0063] In one aspect of the invention, the method involves shedding the electrical loads of the high-voltage bus as a further reaction to the fact that a transmission of the vehicle is in park or idle.

[0064] In one aspect of the invention, the method involves shedding the electrical loads of the high-voltage bus as a further reaction to a reduction in the high-voltage load threshold.

[0065] In one aspect of the invention, the high-voltage load threshold is based on a low-voltage bus load and a buffer low-voltage bus load.

[0066] According to the present invention, a vehicle system is provided comprising: an internal combustion engine; an electric machine; a traction battery; a high-voltage bus electrically coupling the electric machine and the traction battery; a controller comprising executable instructions stored in non-transient memory which cause the controller to lower a high-voltage load threshold in response to the traction battery's state of charge (SOC) being discharged over a plurality of time intervals.

[0067] According to one embodiment, the invention is further characterized by additional executable instructions stored in non-transient memory, which cause the controller to lower the high-voltage load threshold via a proportional / integral (PI) control.

[0068] According to one embodiment, the high-voltage load threshold is an output of the PI controller, and a minimum target traction battery SOC is an input to the PI controller.

[0069] According to one embodiment, the high-voltage load threshold is a quantity of power that can be transmitted via the high-voltage bus.

[0070] According to one embodiment, the high-voltage load threshold is based on a maximum electrical load supported by the internal combustion engine and the electric machine.

[0071] According to one embodiment, the high-voltage load threshold is further based on a low-voltage bus load and a buffer load.

[0072] According to one embodiment, the invention is further characterized by additional executable instructions which cause the control system to throttle high-voltage power consumers that are electrically coupled to the high-voltage bus in response to the high-voltage load threshold.

[0073] According to one embodiment, the invention is further characterized by a gearbox coupled to the electric machine and additional executable instructions which cause the control to lower the high-voltage load threshold while the gearbox is engaged for driving.

[0074] According to the present invention, a method for operating a vehicle comprises the following: lowering a high-voltage power consumption threshold in response to a high-voltage battery state of charge (SOC) being lower than a minimum target high-voltage battery SOC.

[0075] In one aspect of the invention, the method involves lowering the high-voltage power consumption threshold as a further response to the fact that a charging capacity of an internal combustion engine and an electric machine is less than the actual total electrical load of the vehicle.

[0076] In one aspect of the invention, the actual total electrical load of the vehicle includes an electrical load of a low-voltage bus.

[0077] In one aspect of the invention, the actual total electrical load of the vehicle includes the electrical load of a high-voltage bus.

[0078] In one aspect of the invention, the electrical load of the high-voltage bus includes a power distribution system to supply electrical power outside the vehicle.

Claims

[1] Methods for operating a vehicle, comprising: Discharging electrical loads from a high-voltage bus in response to the electrical loads of the high-voltage bus exceeding the electrical power generation capacity of a motor and electric machine for motor speeds below a threshold speed. [2] Method according to claim 1, further comprising throttling electrical loads of the high-voltage bus in response to the fact that the electrical loads of the high-voltage bus exceed the electrical power generation capacity of the motor and the electric machine for motor speeds below the threshold speed. [3] Method according to claim 1, further comprising shedding the electrical loads of the high-voltage bus as a further reaction to the fact that a high-voltage battery SOC discharges over a plurality of predetermined threshold periods. [4] Method according to claim 1, further comprising shedding the electrical loads of the high-voltage bus as a further reaction to the fact that an internal combustion engine of the vehicle is operated within a predetermined threshold of a maximum available engine torque at a current engine speed. [5] Method according to claim 1, further comprising shedding the electrical loads of the high-voltage bus as a further reaction to the fact that a transmission of the vehicle is in park or idle. [6] Method according to claim 1, further comprising shedding the electrical loads of the high-voltage bus as a further reaction to the fact that a high-voltage load threshold is reduced. [7] Method according to claim 6, wherein the high-voltage load threshold is based on a low-voltage bus load and a buffer low-voltage bus load. [8] Vehicle system, including: an internal combustion engine; an electric machine; a traction battery; a high-voltage bus that electrically couples the electric machine and the traction battery; a controller which includes executable instructions stored in non-transient memory that cause the controller to lower a high-voltage load threshold in response to the traction battery's state of charge (SOC) depleting over a variety of time intervals. [9] Vehicle system according to claim 8, further comprising additional executable instructions stored in non-transient memory which cause the controller to lower the high-voltage load threshold via a proportional / integral (PI) control. [10] Vehicle system according to claim 9, wherein the high-voltage load threshold is an output of the PI control and wherein a minimum target traction battery SOC is an input to the PI control. [11] Vehicle system according to claim 8, wherein the high-voltage load threshold is a quantity of power that can be transmitted via the high-voltage bus. [12] Vehicle system according to claim 11, wherein the high-voltage load threshold is based on a maximum electrical load supported by the internal combustion engine and the electric machine. [13] Vehicle system according to claim 12, wherein the high-voltage load threshold is further based on a low-voltage bus load and a buffer load. [14] Vehicle system according to claim 8, further comprising additional executable instructions which cause the control system to throttle high-voltage power consumers that are electrically coupled to the high-voltage bus in response to the high-voltage load threshold. [15] Vehicle system according to claim 14, further comprising a transmission coupled to the electric machine and additional executable instructions which cause the control to lower the high-voltage load threshold while the transmission is engaged for driving.

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