Abstract: Distributed maximum power point tracking systems, structures, and processes are provided for power generation structures, such as for but not limited to a solar panel arrays. In an exemplary solar panel string structure, distributed maximum power point tracking (DMPPT) modules are provided, such as integrated into or retrofitted for each solar panel. The DMPPT modules provide panel level control for startup, operation, monitoring, and shutdown, and further provide flexible design and operation for strings of multiple panels. The strings are typically linked in parallel to a combiner box, and then toward and enhanced inverter module, which is typically connected to a power grid. Enhanced inverters are controllable either locally or remotely, wherein system status is readily determined, and operation of one or more sections of the system are readily controlled. The system provides increased operation time, and increased power production and efficiency, over a wide range of operating conditions.

Abstract: A system and method for operating an electric vehicle. In another exemplary embodiment, a system for operating an electric vehicle is disclosed. The system includes a first motor and a transmission coupled to the first motor. The transmission is configured to shift gears when a speed of the electric vehicle crosses a shift threshold. The shift threshold is independent of a position of an acceleration pedal of the electrical vehicle.

Abstract: Power transfer system for supplying electric power to a battery of an electric vehicle including a control architecture capable of controlling the transmission of electric power to a battery of said electric vehicle and, at the same time, capable of providing fast responsive control functionalities. In a further aspect, the application relates to a method for controlling a power transfer system.

Abstract: A rack system for a main motor vehicle, comprising: a rack unit mountable to a rear side of the main motor vehicle, wherein the rack unit is configured to carry at least one electric auxiliary vehicle comprising at least one battery unit to power the electric auxiliary vehicle; an electric charging unit configured to electrically charge the battery unit of the at least one electric auxiliary vehicle with more than 12 Volts; wherein the electric charging unit is arranged at the rack unit.

Abstract: A method for operating a system for ascertaining a state of charge of a battery of a motor vehicle includes providing operating variables of the battery, providing a calculated state of charge in the motor vehicle using a state-of-charge model that indicates a calculated state of charge depending on at least one battery model parameter of the state-of-charge model for the battery, and ascertaining a reference state of charge using a reference state-of-charge model depending on the operating variables. The reference state-of-charge model is trained to indicate the reference state of charge depending on the operating variables and/or a predefined aging state. The method further includes performing a correction of the at least one battery model parameter depending on a difference between the reference state of charge and the calculated state of charge in order to adapt the calculated state of charge to the reference state of charge.

Abstract: A vehicle-mounted charging device is provided. The vehicle-mounted charging device includes a main body unit, at least one wireless charging coil and a plurality of wired charging units. The main body unit receives an input power, and provides at least one wireless charging power and a plurality of wired charging powers. The wireless charging coil is coupled to the main body unit for receiving the corresponding wireless charging power, and the wireless charging coil charges a wireless electronic device disposed thereon through electromagnetic coupling. Each wired charging unit includes a wire and an input terminal and an output terminal which are located at two sides of the wire respectively. The input terminal is coupled to the main body unit for receiving the corresponding wired charging power. The wired charging power is transmitted to the output terminal so as to charge the wired electronic device connected to the output terminal.

Abstract: A system is provided. The system can include a charger. The charger can electrically connect with a vehicle. The charger can transmit, responsive to occurrence of a triggering event, a first signal to the vehicle. The first signal can have a first voltage to cause the vehicle to direct a first power to the charger. The charger can transmit a second signal to the vehicle. The second signal can have a second voltage to cause the vehicle to direct a second power to the charger. The charger can supply the second power to a load connected to the charger.

Abstract: A system and method for charging and stacking electric transport devices is described. In one embodiment, an electric transport device charging system includes a charging mat including a plurality of charging terminals. The plurality of charging terminals have a first shape. The system also includes a plurality of electric transport devices. Each electric transport device has a pair of side surfaces including a plurality of connection points. The connection points on one of the side surfaces having a second shape that is configured to conform to the first shape of the plurality of charging terminals. A first electric transport device of the plurality of electric transport devices is configured to be placed on the charging mat with the plurality of charging terminals aligned with the connection points on one of the side surfaces having the second shape such that the connection points and the charging terminals fit into each other.

Abstract: A contactor control system includes a switching member, a high voltage load, a high voltage energy storage, a bi-directional DC/DC-converter operatively connected to the switching member, a high-voltage capacitor operatively connected to the high-voltage load, and a low voltage energy storage operatively connected to the bi-directional DC/DC-converter, wherein the switching member is adapted to connect and disconnect the high voltage energy storage to and from the high voltage load, where the bi-directional DC/DC-converter is adapted to pre-charge the high-voltage capacitor to a predefined voltage value from the low voltage energy storage before the switching member is closed and adapted to discharge the high-voltage capacitor to the low voltage energy storage when the switching member has been opened. The advantage of the invention is that a DC-link capacitor can be charged from and discharged to a low voltage battery by using a bi-directional DC/DC-converter. Energy losses can thus be minimized.

Abstract: A vehicle charging system comprises at least one controller and at least one arm, each arm having a first end coupled an actuator and a second end comprising a charging interface. The actuator is configured to articulate the arm into a charging position. The charging interface comprises at least one charging contact coupled to a power source and configured to engage and deliver power to a vehicle charging interface to charge at least one battery of a vehicle. The charging system can include a plurality of arms, each configured to charge a different vehicle. A method of charging one or more vehicles using the charging system is also provided.

Abstract: A system for determining a relative pose between a primary winding structure and a secondary winding structure of a system for inductive power transfer. The system includes at least a first pose determining means for determining a relative pose, wherein the relative pose is determinable by the first pose determining means. The system further includes at least one correcting means for correcting the pose determination by the first pose determining means. A correction of the pose determination is adjustable.

Abstract: A battery current measuring device includes a switching element configured to control charging and discharging of a battery, an A/D converter configured to convert a voltage value across the switching element into a digital value, a temperature compensation unit having a diode structure capable of compensating for a resistance change according to a change of temperature of the switching element, and a current calculation unit configured to calculate a current flowing through the switching element based on the digital value of the voltage value, and the A/D converter converts the voltage value of the switching element into the digital value using a reference voltage inputted from the temperature compensation unit.

Abstract: Embodiments of this application provide an energy conversion apparatus, a power system, and a vehicle. The energy conversion apparatus includes a first switch group, a second switch group, a third switch group, a three-phase converter, a motor coil, a bridge arm circuit, and a three-port converter. The energy conversion apparatus is integrated with functions of alternating-current charging, motor driving, and direct-current charging, and can be installed on an electric vehicle to improve vehicle integration, thereby simplifying a structural layout of the electric vehicle, and reducing costs and a volume of the electric vehicle.

Abstract: Disclosed is a cooler according to various embodiments of the disclosure. The cooler may have an electronic device mounted thereon, which includes a front surface on which a display area is formed and a rear surface opposite the front surface. The cooler may include a housing including a first surface, a second surface opposite the first surface, and a third surface that surrounds an interior space between the first surface and the second surface, the first surface including a seating area on which the rear surface of the electronic device is seated and a recess area spaced apart from the rear surface of the electronic device by a predetermined gap, and a fan disposed in the interior space of the housing and including a rotary shaft formed in a direction toward the first surface from the second surface.

Abstract: Techniques for charging a battery associated with a vehicle are discussed herein. A dense charging station for charging the battery may have lanes arranged in parallel, and each of the lanes may have sequential charging locations. A vehicle utilizing the charging station may position itself at the first available charging location, being receiving energy, and determine if a subsequent charging station becomes available in the lane, and then position itself at the subsequent charging location, once available. Multiple charging stations may be required to maintain a threshold power state for individual vehicles in a fleet of vehicles providing a service for a geographic region. A charging coordinator may determine when a battery of a vehicle does not satisfy a threshold power state and requires a recharge. Additionally, the charging coordinator may determine a candidate charging station from among multiple charging stations associated with the geographic region.

Abstract: When software of a first electronic control unit that controls charging of an auxiliary machinery battery from a power supply by controlling a charging device is rewritten, an onboard system is configured so that charging of the auxiliary machine battery from the power supply is controlled by one or more electronic control units different from the first electronic control unit. Accordingly, even when the software of the first electronic control unit that controls the charging of the auxiliary machinery battery is rewritten, the auxiliary machinery battery can be charged by one or more electronic control units different from the first electronic control unit when the software is rewritten, and the power for rewriting the software of the first electronic control unit can be secured. This can ensure power to rewrite the software of the first electronic control unit.

Abstract: Systems and methods for operating a driveline of a hybrid vehicle are presented. In one example, a boost phase of a procedure to close a driveline disconnect clutch may be cut short in response to an engine changing state from not rotating to rotating so that the engine may be restarted in an alternative way. The system and methods may also predict a degraded engine start from a low engine cranking speed or a long cranking time duration so that the engine may be started in an alternative way to increase a possibility of starting the engine and decrease the severity of degraded driveline disturbance.

Abstract: A wireless charging system for recharging batteries in a medical environment includes a charging station. The charging station may include an opening to receive batteries and an outlet for dispensing charged batteries, wherein the outlet comprises a slot in a front cover. The charging station also includes a wireless power transmitter having a transmitting antenna.

Abstract: A computer includes a processor and memory stores instructions executable by the processor to receive a message sent by a first electronic control unit of a deactivated vehicle via a vehicle network of the deactivated vehicle, the message including a power consumption level indicating a rate of power consumption currently used by the first electronic control unit, send a second message to a user device when the power consumption level of the first electronic control unit exceeds a threshold, the second message including a request to deactivate the first electronic control unit, and deactivate the first electronic control unit upon receiving, in response to the request, user input to deactivate the first electronic control unit.

Abstract: A power system for a vehicle includes a traction battery having an output voltage, a transformer including a coil, and a power converter including a plurality of capacitors and a plurality of switches arranged such that when a first subset of the switches are ON, two of the capacitors are in parallel, an AC voltage across the coil is in a positive half cycle, and a voltage across each of the two of the capacitors is half the output voltage.

Abstract: A method for estimating a power limit of a battery pack is disclosed, including: obtaining an actual minimum cell voltage of an electrical core with a minimum voltage in the battery pack; obtaining a static discharge power limit of the battery pack; calculating, based on the actual minimum cell voltage, an estimated discharge voltage of the electrical core with the minimum voltage for use when the battery pack is discharged based on the static discharge power limit; determining whether the estimated discharge voltage falls between a discharge voltage control threshold of the electrical core with the minimum voltage and an undervoltage threshold of the electrical core with the minimum voltage; and determining a target discharge power limit of the battery pack through a discharge interpolation algorithm when the estimated discharge voltage falls between the discharge voltage control threshold and the undervoltage threshold.

Abstract: A power system includes a charge circuit connecting a low voltage circuit to a high voltage circuit; a charge control unit configured to execute an auxiliary charge control to charge a low voltage battery; a BCM configured to accept an ON operation or an OFF operation; and an auxiliary charge timing setting unit configured to set an auxiliary charge timing at which the auxiliary charge control is to be executed during a standstill period, the standstill period starting from acceptance of the OFF operation and ending at acceptance of the ON operation. If a soak time is shorter than an auxiliary charge-allowing period, the charge control unit executes the auxiliary charge control at the auxiliary charge timing set by the auxiliary charge timing setting unit, whereas if the soak time is longer than the auxiliary charge-allowing period, the charge control unit does not execute the auxiliary charge control.

Abstract: A vehicle includes an electric-device temperature acquisition unit, a charging controller, and a predicted charging time deriving unit. The electric-device temperature acquisition unit acquires a temperature of an electric device disposed in a current path for external charging for supplying electric power from a power supply external to the vehicle to a battery mounted in the vehicle. The charging controller pauses a supply of electric power to the battery in response to the temperature of the electric device becoming greater than or equal to a first threshold during the external charging, and resumes the supply of electric power to the battery in response to the temperature of the electric device becoming less than a second threshold lower than the first threshold. The predicted charging time deriving unit derives a predicted charging time predicted to be taken for the external charging in accordance with an instruction for the external charging.

Abstract: A 12 volt automotive battery system includes a first battery coupled to an electrical system, in which the first battery include a first battery chemistry, and a second battery coupled in parallel with the first battery and selectively coupled to the electrical system via a first switch, in which the second battery includes a second battery chemistry that has a higher coulombic efficiency than the first battery chemistry. The first switch couples the second battery to the electrical system during regenerative braking to enable the second battery to capture a majority of the power generated during regenerative braking. The 12 volt automotive battery system further includes a variable voltage alternator that outputs a first voltage during regenerative braking to charge the second battery and a second voltage otherwise, in which the first voltage is higher than the second voltage.

Abstract: A method for controlling air conditioning of a vehicle includes: determining whether an air conditioning control entry condition for battery cooling wind backseat backflow compensation is satisfied from environment information collected from the vehicle; starting air conditioning control for the battery cooling wind backseat backflow compensation if it is determined that the entry condition is satisfied; determining a compensation value corresponding to a current operating level of a battery cooling fan when the air conditioning control for the battery cooling wind backseat backflow compensation is started; compensating for a current control variable value of an air conditioning device component using the determined compensation value; and performing an air conditioning operation for compensation in accordance with a backflow of a battery cooling wind having cooled a battery toward a backseat by controlling a state of the air conditioning device component in accordance with the compensated control variable va

Abstract: An electrically driven vehicle includes a battery pack including a battery ECU, a gate ECU provided separately from the battery pack, and an HVECU provided separately from the battery pack and the gate ECU and configured to control any one of battery power and battery current of the battery as a control target. The gate ECU is installed at a position outside the battery pack and relays communication between the battery ECU and the HVECU.

Abstract: A vehicle battery charger and a vehicle battery charging system are described and illustrated, and can include a controller enabling a user to enter a time of day at which the vehicle battery charger or system begins and/or ends charging of the vehicle battery. The vehicle battery charger can be separate from the vehicle, can be at least partially integrated into the vehicle, can include a transmitter and/or a receiver capable of communication with a controller that is remote from the vehicle and vehicle charger, and can be controlled by a user or another party (e.g., a power utility) to control battery charging based upon a time of day, cost of power, or other factors.

Abstract: A powertrain system includes an engine coupled to a turbocharger and a timer, a motor generator coupled to the engine and a battery, and a controller. The controller is structured to receive data indicative of a state of charge from the battery, determine whether the state of charge is at or below a high predefined threshold, modulate control on the engine and the timer in response to determining the state of charge is above the high predefined threshold, determine whether the state of charge is above a low predefined threshold in response to the state of charge being at or below the high predefined threshold, and modulate control of the engine and the timer in response to determining the state of charge is at or below the low predefined threshold.

Abstract: An electrical plug connector includes a connector housing receiving an electrical terminal. The connector housing has an outer cooling gas connection cooling an electrical plug-in connection of the plug connector with a mating plug connector. A cooling gas is brought into the plug connector by the outer cooling gas connection through a cooling gas channel of the connector housing.

Abstract: A hybrid powertrain system and method includes a prime mover driving a generator/motor to produce an AC power output. The AC power output is applied to a rectifier which is controlled to transform the applied AC power to DC power to supply a DC Power bus at a selected voltage and current. An energy storage device is also connected to the DC power bus and the current flow between the energy storage device and the DC power bus is monitored and compared to preselected values and the results of that comparison are used to alter the operation of the rectifier to increase or decrease, as needed, the current provided to the DC power bus as electrical loads on the DC power bus change.

Abstract: Systems and methods for operating an electric energy storage system are described. The systems and methods include ways of coupling electric energy storage cell stacks to an electric conductor or bus. The coupling is performed to reduce current flow through contactors and to increase a life span of the contactors.

Abstract: Set forth herein are systems and methods for determining battery heating conditions and pre-heating lead times of at least a minute or more, based on input parameters and sets of input parameters, to predictively and dynamically heat a secondary battery so that the battery has a specific power output and performance level when used in an electric or hybrid vehicle application.

Abstract: A device for charging an electric vehicle includes a charging inlet for receiving charging information and power from electric vehicle supply equipment (EVSE); a control module for determining a charging mode on the basis of the charging information, and outputting a control signal according to the determined charging mode; and a charging unit for charging a battery of the electric vehicle according to the control signal from the control module.

Abstract: A system for charging a battery within an at least partially electric vehicle. The system includes a charging device wherein the charging device configured to electrically connect to the at least partially electric vehicle and charge at least one battery by a predetermined amount. The system also includes a network configured to determine the location of the charging device.

Abstract: A vehicle includes a high-voltage system circuit including a high-voltage battery; a low-voltage system circuit including a low-voltage battery and an updater; a DC-DC converter coupled between the two circuits; and a controller that controls the two circuits and the DC-DC converter. The updater updates a program of an update-target device. The DC-DC converter reduces in voltage output electric power of the high-voltage battery and then supplies the electric power to the low-voltage system circuit. The controller determines whether the update-target device is a certain device relating to electric power supply from the high-voltage battery. If the update-target device is the certain device, the low-voltage battery is charged with the output electric power of the high-voltage battery, the certain device stops operating, and the updater updates the program of the certain device by using the output electric power of the low-voltage battery.

Abstract: Disclosed herein is a compliant joint that is movable in three degrees of freedom (DOF), as well as systems including the compliant joint, and a process for assembling the compliant joint. The compliant joint may comprise an elongate arm, a ball joint, and a carrier. The ball joint is configured to couple to the carrier, and the elongate arm is configured to couple to the ball joint. The ball joint may have a cross section that is ellipsoidal, an outer surface that is convex, and a first hole. The carrier may comprise a second hole that is ellipsoidal, and an inner surface that is concave. The elongate arm, when disposed within the first hole, is movable axially through the first hole, and the ball joint, when disposed within the second hole, is movable with at least one of pitch rotation or yaw rotation.

Abstract: A program update method includes a first step of acquiring a remaining capacity of electric power stored in an electric power storage device, a second step of acquiring an electric power amount required for the control device to update the control program, a third step of determining whether the remaining capacity is smaller than the electric power amount, a fourth step of charging the electric power storage device such that the remaining capacity becomes the electric power amount or larger when it is determined that the remaining capacity is smaller than the electric power amount in the third step, and a fifth step of causing the control device to update the control program when the remaining capacity becomes the electric power amount or larger in the fourth step. The first to fifth steps are performed when the vehicle is operating.

Abstract: A battery and a load device are connected to a fuel cell stack. Electric power is supplied from the battery to fuel cell auxiliary equipment. A controller of a fuel cell system has stored therein a desired output of the fuel cell stack. The controller predicts auxiliary equipment power consumption, which is the amount of electric power that is consumed by the fuel cell auxiliary equipment for operation of the fuel cell stack, and determines estimated input and output power of the battery. The controller determines a requested output, which is an output requested for the fuel cell stack, based on the predicted auxiliary equipment power consumption and the estimated input and output power. The controller determines an operating point of the fuel cell stack based on the desired output. The load device controls its operation so that the difference between the requested output and the desired output becomes zero.

Abstract: A battery pack has a battery connection assembly for connecting to an electric motor with at least one lithium-based rechargeable cell therein and associated means for turning the at least one lithium-based rechargeable cell ON or OFF. The battery pack is configured to store a reserve within the at least one lithium-based rechargeable cell that is sufficient to start the engine electric motor. The battery pack can be activated by the associated means for turning the at least one lithium-based rechargeable cell ON or OFF to access the reserve to start the engine electric motor.

Abstract: A power supply device is mountable to a vehicle and includes: a high-voltage battery; a low-voltage battery of which an output voltage is lower than that of the high-voltage battery, and which can be charged by output power from the high-voltage battery; and a control unit configured to perform charging/discharging control for the high-voltage battery and the low-voltage battery. The control unit performs feeding control for causing the high-voltage battery to supply power to a predetermined on-vehicle device while consumed power is higher than a predetermined value in a state in which a main switch of the vehicle is not on.

Abstract: A mechanism is described for facilitating storage management for machine learning at autonomous machines. A method of embodiments, as described herein, includes detecting one or more components associated with machine learning, where the one or more components include memory and a processor coupled to the memory, and where the processor includes a graphics processor. The method may further include allocating a storage portion of the memory and a hardware portion of the processor to a machine learning training set, where the storage and hardware portions are precise for implementation and processing of the training set.

Abstract: An improved method and apparatus for powering an electric motor for starting an internal combustion engine in which the electric motor is in a 6 volt to 48 volt operating system, in which an auxiliary battery pack has a battery pack housing; at least one lithium-based rechargeable cell within the housing; associated means for receiving a radio transmitted signal; associated means for turning the rechargeable cell ON or OFF; and battery connections for connecting the auxiliary battery pack to a battery in a 6 volt to 48 volt operating system.

Abstract: A power system within a battery-powered node includes a primary cell, a secondary cell, and a battery controller. The battery controller includes a constant current source that draws power from the primary cell to charge the secondary cell. The battery-powered node draws power from the secondary cell across a wide range of current levels. When the voltage of the secondary cell drops beneath a minimum voltage level, the constant current source charges the secondary cell and a charging signal is sent to the battery-powered node. When the voltage of the second cell exceeds a maximum voltage level, the constant current source stops charging the secondary cell and the charging signal is terminated. The battery-powered node records the amount of time the charging signal is active and then determines a battery depletion level based on that amount of time. Battery replacement may then be efficiently scheduled based on the depletion level.

Abstract: A power electronics charge coupler (PECC) unit allows vehicle-to-vehicle (V2V) energy transfer by forming a bidirectional buck/boost converter for supplying rapid energy transfer with wide input-output battery voltage and battery voltage levels. The PECC unit embeds DC-DC converter modules into the charging handles of the PECC unit. Each of the charging handles includes a half-bridge of the DC-DC converter and parasitic inductance of a cable between charging handles is utilized as a portion of the filter inductor for the converter. The PECC unit handles are each configured to connect to an electric vehicle and are dynamically configurable in one of four modes of operation based on the battery voltage of the electric vehicles to which the PECC unit is connected and based on which of the electric vehicles is designated as the receiver vehicle and which is designated as the supplier vehicle.

Abstract: A switch arrangement for providing alternative distribution paths in a system for distributing electrical power in a vehicle including electrical power supplies and electrical loads. The switch arrangement includes a first switch configured to be connected to a first electrical element, a second switch configured to be connected to the first electrical element and a second electrical element, and a third switch configured to be connected to the second electrical element and a third electrical element. Each of the first, second, and third switches is independently controllable, and selective operation of each of the first, second, and third switches to its open or closed state interconnects at least two of the first, second, and third electrical elements to establish one of multiple alternative distribution paths to connect one of the power supplies and one of the loads or to connect two of the power supplies.

Abstract: This disclosure describes electric vehicle supply equipment (EVSE) connectors for synchronizing and controlling charging between multiple electric vehicle supply equipment and an electrified vehicle. An exemplary EVSE connector is connectable to a charge port assembly of an electrified vehicle and includes a first port configured to receive a first charger coupler of a first EVSE and a second port configured to receive a second charger coupler of a second EVSE. The EVSE connector further includes a control system for coordinating charging operations between the first and second EVSE and the electrified vehicle.

Abstract: According to one embodiment, there is provided a composite. The composite includes active material particles of a titanium composite oxide or oxide of titanium, and a graphene structure including a carbon material. The carbon material has a graphene framework defining a graphene surface. The graphene structure is located in between the active material particles. The graphene structure has at least one side surface in contact with the active material particle. The side surface includes the carbon material whose graphene surface is slanted relative to the side surface.

Abstract: A straddle-type electric vehicle includes two approximately rectangular parallelepiped batteries, a battery case in which the batteries are housed, battery-side terminals provided on bottom surfaces of the batteries, and case-side terminals engaged with the battery-side terminals. The two batteries are arranged next to each other in a vehicle width direction. An operation lever for connecting or separating the battery-side terminals and the case-side terminals to/from each other is provided. The operation lever is arranged in a middle in the vehicle width direction between the two batteries, and the battery-side terminals and the case-side terminals are arranged nearer outer sides in the vehicle width direction. A pair of front and rear link mechanisms for coupling the operation lever and the case-side terminals to each other is provided in front of and behind the battery case.

Abstract: There is provided an electrically driven vehicle used for a car sharing system and configured to appropriately increase the temperature of a power storage device. The electrically driven vehicle used for the car sharing system is provided with a power storage device and a temperature raising device configured to increase temperature of the power storage device. When a user operates a communication device to make a direct reservation or an indirect reservation of the electrically driven vehicle for driving, the electrically driven vehicle estimates a driving start time of the vehicle, based on the position of the communication device, sets a temperature-rising start time of the power storage device, based on the temperature of the power storage device and the estimated driving start time, and controls the temperature raising device to start a temperature increase of the power storage device at the set temperature-rising start time.

Abstract: Disclosed is a transport refrigeration system including: an engine that is dedicated to the transport refrigeration system; a primary battery that is dedicated to the transport refrigeration system, the primary battery being electrically connected to the engine; and a jumper battery electrically connected to the primary battery, the jumper battery configured to automatically boost the primary battery when the primary battery fails to start the engine.