Powertrain

A powertrain is the set of components that generates power and delivers it to a vehicle's drive wheels. It encompasses the energy source, the prime mover, and the components that convert and transmit power to the wheels. In conventional automobiles, the powertrain typically includes the internal combustion engine, the transmission, the driveshaft or final drive, the differential, and the axles. In electric vehicles, the term often expands to cover the electric motor(s), the traction battery, and the power electronics and motor controllers, with the transmission sometimes simplified or omitted.

Components and roles: The energy source may be gasoline, diesel, electricity, or hydrogen. The prime mover converts stored energy into mechanical torque. The transmission adjusts speed and torque and may be a manual, automatic, continuously variable (CVT), or dual-clutch design. The drivetrain transmits torque to the wheels and may include a driveshaft, differential, and axles. Power electronics, cooling, and lubrication systems support operation.

Types and trends: Traditional internal combustion engine powertrains face efficiency and emissions constraints, leading to hybrids that combine an engine and electric motors, and fully electric powertrains that rely on battery packs and inverters. Vehicle layouts vary by drive configuration (front-, rear-, or all-wheel drive) but all share the same goal: deliver power efficiently from source to wheels.

Performance and maintenance: Powertrain efficiency, torque delivery, regenerative braking, and maintenance of components are central concerns. Advances in electrification and software controls continue to reshape powertrain design.