Methods and systems are provided for a vehicle system. In one example, the vehicle system includes a first electric drive axle assembly and a second electric drive axle assembly. Each of the first and second axle assemblies has a gear train with a planetary gear set axially offset from a motor-generator and each planetary gear set is rotationally coupled to a differential.

A dog clutch engagement method of an electric four-wheel drive vehicle includes steps of: when dog clutch engagement is requested during driving, determining a target synchronization speed of the input gear to be a sum of an estimated speed and an offset speed of the output gear; operating a drive unit so that an input gear follows the target synchronization speed; when an actual speed of the input gear reaches the target synchronization speed, moving a sleeve to a meeting position at which the sleeve is in contact with the input gear; and when the actual speed of the input gear is synchronized with an actual speed of the output gear, transporting the sleeve to an engagement position at which the input gear and the output gear are coupled.

A system includes a clutch state module and a clutch torque module. The clutch state module is configured to determine whether a clutch of an electronic limited slip differential is locked or unlocked. The electronic limited slip differential couples an engine of a vehicle to left and right wheels of the vehicle. The clutch torque module is configured to estimate an actual torque transferred by the clutch using a first clutch torque model when the electronic limited slip differential is unlocked, and estimate the actual clutch torque using a second clutch torque model when the electronic limited slip differential is locked. The second clutch torque model is different than the first clutch torque model.

A vehicle may include a CVT unit or a power source which requires ambient air. An air inlet for an air intake system coupled to the CVT unit or the power source which requires ambient air may be provided in a side of a cargo carrying portion of the vehicle. The vehicle may include a rear radius arm suspension.

Vehicles may be composed of a relatively few number of “modules” that are assembled together during a final assembly process. An example vehicle may include a body module, a first drive module coupled to a first end of the body module, and a second drive module coupled to a second end of the body module. One or both of the drive modules may include a pair of wheels, a battery, an electric drive motor, and/or a heating ventilation and air conditioning (HVAC) system. One or both of the drive modules may also include a crash structure to absorb impacts. If a component of a drive module fails or is damaged, the drive module can be quickly and easily replaced with a new drive module, minimizing vehicle down time.

A vehicle speed is lower than a first threshold, a control device controls both a first drive unit and a second drive unit to output a requested driving force by setting an operation mode of the first drive unit to a first mode when the requested driving force is smaller than a second threshold and the charge level of a power storage device is equal to or higher than a third threshold, and controls both the first drive unit and the second drive unit to output the requested driving force by setting the operation mode of the first drive unit to a second mode when the requested driving force is equal to or larger than the second threshold or the charge level of the power storage device is lower than the third threshold.

A control method for an electric four-wheel drive vehicle including a front drive source for driving a front wheel and a rear drive source for driving a rear wheel independently of the front wheel includes: acquiring a driving direction of the electric four-wheel drive vehicle based on an input state of a shift lever; acquiring an actual moving direction of the electric four-wheel drive vehicle; and when the driving direction and the moving direction are different from each other, setting a basic driving force for suppressing movement in the moving direction for the front wheel and the rear wheel, and driving one wheel of the front wheel and the rear wheel with a driving force smaller than the basic driving force by implementing a limit for setting an upper limit value for a driving force generated in the one wheel.

A vehicle drive device includes a first drive unit that drives first wheels; a second drive unit that drives second wheels; and a control device. When the state of charge of an electrical storage device is less than a first threshold value and a vehicle speed is less than a second threshold value, the control device performs control such that when the vehicle speed is greater than or equal to zero and required drive power is greater than or equal to zero, the operating mode of the first drive unit is set to a second mode to output the required drive power from the second drive unit, and when the vehicle speed is greater than zero and the required drive power is less than zero, the operating mode of the first drive unit is set to a first mode so the first drive power source can generate electric power.

A powertrain system for a vehicle is described. The powertrain system includes a first energy storage unit, a second energy storage unit, and an electronic control unit coupled to the first energy storage unit and the second energy storage unit. The first energy storage unit is configured to provide power to drive a first set of wheels of the vehicle. The second energy storage unit is configured to provide power to drive a second set of wheels of the vehicle different from the first set of wheels. The first and second energy storage units have different energy storage and/or energy discharge characteristics. The electronic control unit is programmed to control a charge and/or a discharge operation of the first energy storage unit and the second energy storage unit. The powertrain system is capable of implementing control strategies for optimizing energy and power to meet various driving demands of the vehicle.

A vehicle may include a CVT unit or a power source which requires ambient air. An air inlet for an air intake system coupled to the CVT unit or the power source which requires ambient air may be provided in a side of a cargo carrying portion of the vehicle. The vehicle may include a rear radius arm suspension.