Patent Publication Number: US-2023151884-A1

Title: Hybrid or electric vehicle

Description:
TECHNICAL FIELD 
     The present disclosure relates to hybrid and electric vehicles. 
     BACKGROUND 
     Electric and hybrid vehicles may include power supply devices that are configured to convert electrical power from direct current (DC) into alternating current (AC) and vice versa. 
     SUMMARY 
     A vehicle includes a drive wheel, an electric machine, a battery, an inverter, a transmission, a pump, a voltage controller, and a controller. The electric machine is configured to deliver and receive mechanical power to and from the drive wheel. The inverter has an input connected to the battery and an output connected to the electric machine. The inverter is configured to convert power between DC electrical power at the input and AC electrical power at the output. The transmission disposed between the electric machine and the drive wheel. The pump is configured to circulate lubricating fluid within the transmission. The voltage controller is configured to deliver DC electrical power from the inverter to the pump. The controller is programmed to, in response to the drive wheel powering the electric machine to generate AC electrical power and the electric machine delivering AC electrical power to the inverter during a towing condition of the vehicle, operate the voltage controller to power the pump. 
     A vehicle includes at least one drive wheel, an electric machine, a traction battery, an inverter, a transmission, an electrically powered pump, and a step-down voltage controller. The electric machine is configured to deliver power to the at least one drive wheel to propel the vehicle. The traction battery is configured to store electrical energy. The inverter has an input and an output. The inverter is configured to receive DC electrical power from the battery at the input, convert the DC electrical power into to AC electrical power, and deliver the AC electrical power to the electric machine at the output. The transmission is disposed between the electric machine and the at least one drive wheel. The electrically powered pump is configured to deliver fluid to lubrication points within the transmission. The step-down voltage controller is configured to deliver the DC electrical power from the input of the inverter to the electrically powered pump in response to the at least one drive wheel powering the electric machine during a towing condition of the vehicle and the electric machine generating and delivering AC electrical power to the inverter. 
     A vehicle includes an inverter, a pump, a buck converter, and a controller. The inverter has an input connected to a battery and an output connected to an electric machine. The inverter is configured to convert power between DC electrical power at the input and AC electrical power at the output. The pump is configured to circulate lubricating fluid within a transmission. The buck converter is configured to deliver DC electrical power from the inverter to the pump. The controller is programmed to, in response to the electric machine delivering AC electrical power to the inverter during a towing condition of the vehicle while the vehicle is shutdown, operate the buck converter to power the pump. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic illustration of a representative powertrain of a hybrid electric vehicle; 
         FIG.  2    is a circuit diagram of a power controller illustrating an inverter that is coupled to a DC power source and an electric machine; and 
         FIG.  3    is a flowchart of a method for powering and controlling a transmission pump during towing condition of the vehicle. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations. 
     Referring now to  FIG.  1   , a hybrid electric vehicle  10  having a powersplit powertrain is illustrated. The powertrain includes two power sources that are connected to the driveline: (1) an engine  16  and an electric machine  50  (which may be referred to as a generator) connected together via a planetary gear arrangement  20 ; and (2) an electric drive system including a battery  12  having a battery control module (BCM), an electric machine  46  (which may be referred to as a motor) and a generator  50 . Battery  12  is an energy storage system for motor  46  and generator  50 . 
     A vehicle system controller (VSC)  11  is configured to send control signals to and receive sensory feedback information from one or more of battery  12 , engine  16 , motor  46 , and generator  50  in order for power to be provided to one or more vehicle drive or traction wheels  40  for propelling the vehicle  10 . Controller  11  controls the power source proportioning between battery  12  and engine  16  for providing power to propel the vehicle  10  and thereby controls the state of charge (SOC) of battery  12 . The battery  12  may more specifically be a traction battery. 
     Transmission  14  includes planetary arrangement  20 , which includes a ring gear  22 , a sun gear  24 , and a carrier assembly  26 . Ring gear  22  distributes torque to step ratio gears comprising meshing gear elements  28 ,  30 ,  32 ,  34 , and  36 . A torque output shaft  38  of transmission  14  is driveably connected to wheels  40  through a differential-and-axle mechanism  42 . Gears  30 ,  32 , and  34  are mounted on a counter shaft  31  with gear  32  engaging a motor-driven gear  44 . Motor  46  drives gear  44 . Gear  44  acts as a torque input for counter shaft  31 . Engine  16  distributes torque through input shaft  18  to transmission  14 . Battery  12  delivers electric power to motor  46  through power flow path  48 . Generator  50  is connected electrically to battery  12  and to motor  46  through power flow path  52 . The power flow paths  48  and  52  may include inverting circuitry to convert direct current power from the battery  12  into alternating current power, which may then be delivered to the motor  46  or generator  50  to increase the power output of the powertrain. The power flow paths  48  and  52  may also include rectifying circuitry to convert alternating current power from either the motor  46  or the generator  50  into direct current power, which may then be delivered to the battery  12  to recharge the battery  12 , which may occur during regenerative braking or while the engine  16  is powering the generator  50 . 
     The motor  46  or the generator  50  may be configured to deliver or receive rotational or mechanical power from the wheels  40  via the gears and shafts within the transmission  14 . If receiving rotational or mechanical power from the wheels  40 , the motor  46  or the generator  50  may then convert into electrical power that is stored as electrical energy in the battery  12 . The motor  46  or the generator  50  may be considered as subcomponents of the transmission  14  or as separate components from the transmission  14 . In either case, all or a portion of the gearing arrangement of the transmission (i.e., the gears and shafts) is disposed between motor  46  or the generator  50  and the wheels  40 . 
     A transmission fluid pump  51  may be configured to circulate lubricating fluid within the transmission  14 . More specifically, the pump  51  may be an electrically powered pump and may be configured to deliver the lubricating fluid to lubrication points within the transmission  14 . Lubrication points may include engagements between shafts and bearings, meshing between gears, etc. In transmissions that include clutches, the pump  51  may also be configured to deliver the fluid to the clutches to engage and disengage the clutches. 
     While battery  12  is acting as a sole power source with engine  16  off, input shaft  18  and carrier assembly  26  are braked by an overrunning coupling (i.e., one-way clutch (OWC))  53 . A mechanical brake  55  anchors the rotor of generator  50  and sun gear  24  when engine  16  is on and the powertrain is in a parallel drive mode, sun gear  24  acting as a reaction element. 
     Controller  11  receives a signal PRND (park, reverse, neutral, drive) from a transmission range selector  63 , which is distributed to transmission control module (TCM)  67 , together with a desired wheel torque, a desired engine speed, and a generator brake command, as shown at  71 . A battery switch  73  is closed after vehicle “key-on” startup. Controller  11  issues a desired engine torque request to engine  16 , as shown at  69 , which is dependent on accelerator pedal position sensor (APPS) output  65 . A brake pedal position sensor (BPPS) distributes a wheel brake signal to controller  11 , as shown at  61 . A brake system control module (not shown) may issue to controller  11  a regenerative braking command based on information from the BPPS. TCM  67  issues a generator brake control signal to generator brake  55 . TCM  67  also distributes a generator control signal to generator  50 . 
     The controllers illustrated in  FIG.  1    (i.e., VSC  11 , BCM, and TCM  67 ) may be part of a larger control system and may be controlled by various other controllers throughout the vehicle  10 . It should therefore be understood that the controllers and one or more other controllers can collectively be referred to as a “controller” that controls various actuators in response to signals from various sensors to control functions such as starting/stopping engine  16 , operating the motor  46  to provide wheel torque, operating the generator to charge the battery  12 , etc. The controllers may include a microprocessor or central processing unit (CPU) in communication with various types of computer readable storage devices or media. Computer readable storage devices or media may include volatile and nonvolatile storage in read-only memory (ROM), random-access memory (RAM), and keep-alive memory (KAM), for example. KAM is a persistent or non-volatile memory that may be used to store various operating variables while the CPU is powered down. Computer-readable storage devices or media may be implemented using any of a number of known memory devices such as PROMs (programmable read-only memory), EPROMs (electrically PROM), EEPROMs (electrically erasable PROM), flash memory, or any other electric, magnetic, optical, or combination memory devices capable of storing data, some of which represent executable instructions, used by the controllers in controlling the vehicle  10 . 
     It should be understood that the vehicle configuration described herein is merely exemplary and is not intended to be limited. Other hybrid or electric vehicle configurations should be construed as disclosed herein. Other vehicle configurations may include, but are not limited to, series hybrid vehicles, parallel hybrid vehicles, series-parallel hybrid vehicles, plug-in hybrid electric vehicles (PHEVs), fuel cell hybrid vehicles, battery operated electric vehicles (BEVs), or any other vehicle configuration known to a person of ordinary skill in the art. 
     It should be understood that the vehicle configuration described herein is merely exemplary and is not intended to be limited. Other electric or hybrid vehicle configurations should be construed as disclosed herein. Other vehicle configurations may include, but are not limited to, series hybrid vehicles, parallel hybrid vehicles, series-parallel hybrid vehicles, plug-in hybrid electric vehicles (PHEVs), fuel cell hybrid vehicles, battery operated electric vehicles (BEVs), vehicles with electric machines connected to each wheel directly or a via step-up or step-down gearing arrangement, or any other hybrid or electric vehicle configuration known to a person of ordinary skill in the art. 
     Referring to  FIG.  2   , a circuit diagram of a power controller (or power supply device)  75  coupled to a power source  77  and an electric machine  79  is illustrated. The power source  77  may be the battery  12  and the electric machine  79  may be the motor  46  or generator  50  described in  FIG.  1   . However, the power controller  75  may be utilized in an electric drive system of any hybrid or electric vehicle configuration. The power source  77  may be coupled to the power controller  75  in order to drive the electric machine  79 . The power controller  75  may include an inverter  81  and a voltage converter  83 . The voltage converter  83  may be a DC to DC boost converter or a step-up DC to DC converter, which is configured to increase the voltage of power source  77  being input into the inverter  81 . The voltage converter  83  includes an inductor. The inverter  81  and the voltage converter  83  may be configured to deliver electrical power to the electric machine  79 . 
     The inverter  81  includes inverting circuitry. The inverting circuitry may include switching units  85 . The switching units  85  may each comprise a transistor  87 , such as an insulated gate bipolar transistor (IGBT), in antiparallel with a diode  89 . The switching units  85  may be configured to provide alternating current to the electric machine  79 . More specifically, the inverter  81  may be configured to convert direct electrical current provided by the power source  77  at an input side  82  of the inverter  81  into alternating electrical current, which is then delivered to the electric machine  79  at an output side  84  of the inverter  81 . The inverter  81  may also be configured to convert alternating electrical current provided by the electric machine  79  at the output side  84  of the inverter  81  into direct electrical current, which is then delivered to the power source  77  at the input side  82  of the inverter  81 . 
     The power controller  75  may include a linking capacitor  91 . The linking capacitor  91  may be disposed between the power source  77  and the inverter  81  at the input side  82  of the inverter  81 . The linking capacitor  91  may be configured to absorb ripple currents generated at the inverter  81  or the power source  77 , and stabilize the DC-link voltage, Vo, for inverter  81  control. Stated in other terms, the linking capacitor  91  may be arranged to limit voltage variation at an input of inverting circuitry due to ripple currents generated by the inverting circuitry or the power source  77 . The power controller  75  may include a drive board  93  for controlling the inverting circuitry. The drive board  93  may be a gate drive board that is configured to operate the transistors  87  of the switching units  85  of the inverter  81  when converting the direct current of the power source  77  into alternating current and delivering the alternating current to the electric machine  79 . 
     The voltage converter  83  may include an inductor. The circuitry of the voltage converter (not shown), including the inductor, may be configured to amplify or increase the voltage of the electrical power being delivered to the electric machine  79  from the power source  77 . A fuse  95  may be disposed on the direct current side of the inverter  81  to protect the inverting circuitry from surges in electrical power. 
     The disclosure should not be construed as limited to the circuit diagram of  FIG.  2   , but should include power control devices that include other types inverters, capacitors, converters, or combinations thereof. For example, the inverter  81  may be an inverter that includes any number of switching units, the power controller  75  may include rectifying circuitry that converts the alternating current of the electric machine  79  into direct current to recharge the power source  77  (e.g., the generator  50  recharging the battery  12  during regenerative braking), and/or the linking capacitor  91  may be configured to couple one or a plurality of inverters to a power source. 
     A voltage controller  97  is configured to deliver DC electrical power from the inverter  81  to the pump  51  and other vehicle accessories  99 . The pump  51  and the vehicle accessories  99  may more specifically require a low-voltage power source (e.g., a 12-Volt power source). The voltage controller  97  converts the higher-voltage DC power at the input side  82  of the inverter  81  to the required lower-voltage power needed to power the pump  51  and other vehicle accessories  99 . The voltage controller  97  may be a DC to DC buck converter or a step-down DC to DC converter that decreases the voltage from the input side  82  of the inverter  81  and delivers the decreased-voltage power to the pump  51  and the vehicle accessories  99 . The voltage controller  97  may be passive type voltage converter or a switching type voltage converter. The vehicle accessories  99  may include, but are not limited to, climate control systems, power steering systems, radios, control interfaces, various controllers, entertainment systems (e.g., monitors, DVD players, etc.), electric heaters, or any other system or device that is electrically operated via the low-voltage power source. 
     A switch  101  may be disposed between the power source  77  and the inverter  81 . The switch  101  may be referred to as battery contactor. The switch  101  being in the opened position may correspond to the vehicle being in a shutdown condition. Another indicator that the vehicle  10  is shutdown may be a “key-off” position of an ignition. 
     Referring to  FIG.  3   , a flowchart of a method  200  for controlling the transmission pump  51  during towing condition of the vehicle  10  is illustrated. The method  200  may be stored as control logic and/or an algorithm within one or more of the vehicle controllers (e.g., VSC  11 , TCM  67 , BCM, etc.). The method  200  is initiated at start block  202 . Next, the method  200  moves on to block  204 . 
     At block  204 , it is determined if the vehicle  10  is shutdown and if the if the vehicle  10  is under a towing condition. The vehicle  10  being shutdown may correspond to the switch  101  being in the opened position, a “key-off” position of an ignition, or any other indicator that the vehicle  10  has not be turned on for normal driving operation. The vehicle  10  being under a towing condition while the vehicle  10  is shutdown may be derived from several factors. For example, (i) a back electromotive force in the electric machine  79  caused by a drive wheel (e.g., wheel  40 ) powering the electric machine  79  (e.g., causing rotation of the rotor of the electric machine  79 ) such that the electric machine  79  generates AC electrical power which is delivered to the output side  84  of the inverter  81 ; (ii) a voltage of the linking capacitor  91  exceeding a threshold, which is caused by the AC electrical power generated via the electromotive force electric machine  79  and being delivered to the inverter  81  (the electrical power is able to flow from the output side  84  of the inverter  81  to the linking capacitor via the diodes  89  of switching units  85 ); (iii) a speed (e.g., a rotational speed) of the drive wheel exceeding a threshold; (iv) a speed of the electric machine (e.g., a rotational speed of the electric machine rotor) exceeding a threshold; or (v) a speed of vehicle  10 , may each be an indicator that the vehicle  10  is under a towing condition if the vehicle  10  is also shutdown. 
     If it is determined that the vehicle  10  is shutdown and is under a towing condition, the method  200  moves on to block  206 , where the voltage controller  97  is operated to deliver DC electrical power from the inverter  81  to the pump  51  and/or the vehicle accessories  99 . The voltage controller  97  may be configured to automatically deliver the DC electrical power from the inverter  81  to the pump  51  and/or the vehicle accessories  99  once it is determined that the vehicle  10  is shutdown and is under a towing condition. Under such an automatic operation, the voltage controller  97  may “wake up” and begin delivering the DC electrical power from the inverter  81  to the pump  51  and/or the vehicle accessories  99  once a sufficient input voltage to the voltage controller  97  is detected. The input voltage may correspond to the voltage of the linking capacitor  91  or may be based on the back electromotive force coefficient of the electric machine  79  that corresponds to a particular motor speed. Other controllers (e.g., VSC  11 , TCM  67 , BCM, etc.) or devices may also “wake up” to deliver power and/or control the pump  51  and/or the vehicle accessories  99  according to a desired algorithm or control logic. 
     The operation of the voltage controller  97  may not be automatic and may be controlled via a controller (e.g., VSC  11 , TCM  67 , BCM, etc.) in order to deliver the DC electrical power from the inverter  81  to the pump  51  and/or the vehicle accessories  99  once it is determined that the vehicle  10  is shutdown and is under a towing condition. The controller may also operate the pump  51  according to a desired algorithm or control logic. For example, the controller may only operate the pump  51  (i) according to a specified duty cycle or (ii) only when the wheel speed is above a specified threshold where lubrication in the transmission gearing is necessary (e.g., above a wheel speed that equates to the shafts, gears, etc. in the transmission rotating above a speed where wear and tear is accelerated beyond what is tolerable if not lubricated). 
     Furthermore, if the vehicle includes multiple separate drivetrains, each including a transmission or geartrain, for different wheels where each separate drivetrain has (i) an electric machine that delivers power to wheels of that particular drivetrain, (ii) each electric machine draws power from an inverter of that particular drivetrain, and (iii) each transmission or geartrain of that particular drivetrain includes an electric pump that can draw power from a voltage controller that is connected to an input side of the inverter of that particular drivetrain, the method  200  may distinguish between wheels that are in a towing mode and wheels that are not in a towing mode in order to operate the electric pumps. For example, (i) if the vehicle includes first and second drivetrains having first and second axles and (ii) if the wheels on the first and second axles are on the ground and spinning during a towing condition while the vehicle is shutdown according to method  200 , first and second voltage controllers drawing power from inverters connected to first and second electric machines generating back electromotive force in the first and second drivetrains, respectively, may be utilized to power first and second electric pumps in the transmissions or geartrains of the first and second drivetrains to lubricate the moving parts in the transmissions or geartrains of the first and second drivetrains, respectively. On the other hand, if the vehicle is raised or hoisted onto a towing vehicle such that the wheels of the first axle are on the ground and spinning but the wheels of the second axle are not on the ground and spinning during a towing condition, only the first electric pump may be operated while the second electric pump remains shutdown. Under such a condition, the components in the second drivetrain (e.g., gears, shafts, etc.) will not be spinning and therefore will not need to be lubricated. 
     Next, the method  200  moves on to block  208  where it is determined if the electric machine  79  is producing an excessive back electromotive force. If the electric machine  79  is not producing an excessive back electromotive force, the method  200  may simply continue operating the pump  51  and/or the vehicle accessories  99  according to block  206  and may return to block  208  after a specified period of time, or the method  200  may recycle back to block  204 . If the electric machine  79  is producing an excessive back electromotive force, the method  200  moves on to block  210 , where direct axis current, Id, is injected into the coils of the electric machine  79  to control or reduce the back electromotive force to a desired level. The direct axis current, Id, may be directed to the coils of the electric machine  79  via the power source  77 . 
     Returning to block  204 . If it is determined that the vehicle  10  is not both shutdown and under a towing condition, the method  200  moves on to block  212 , where the method  200  ends. The step at block  212  may coincide with the voltage controller  97 , the pump  51 , accessories  99 , and any other electrical device (e.g., VSC  11 , TCM  67 , BCM, etc.) remaining shutdown or being shutdown. 
     It should be understood that the flowchart in  FIG.  3    is for illustrative purposes only and that the method  200  should not be construed as limited to the flowchart in  FIG.  3   . Some of the steps of the method  200  may be rearranged while others may be omitted entirely. 
     It should be understood that the designations of first, second, third, fourth, etc. for any component, state, or condition described herein may be rearranged in the claims so that they are in chronological order with respect to the claims. Furthermore, it should be understood that any component, state, or condition described herein that does not have a numerical designation may be given a designation of first, second, third, fourth, etc. in the claims if one or more of the specific component, state, or condition are claimed. 
     The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments may be combined to form further embodiments that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics may be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. As such, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for particular applications.