A powertrain is a system inside a vehicle, boat or another type of machinery. The system is designed to propel the vehicle forward. In a car, a powertrain consists of the engine or motor and its internal components, such as the energy storage system, transmission and driveshaft. In a conventional internal combustion engine (ICE), the powertrain converts the stored gasoline or diesel energy to kinetic energy in the engine and transfers it via the transmission, driveshaft and differential as torque to the wheels of the vehicle, propelling it forward.
The vast majority of powertrain systems in production today are based on ICEs. These can either be spark ignition (SI) in the case of gasoline or compression ignition (CI) for diesel. Electrification of road vehicles has significantly increased the production of both hybrid engines, which use a mix of ICE and electrified powertrains, and fully electrified systems. The energy for electrified systems can come from a range of sources, including onboard generation, plug-in charging or even hydrogen fuel cells.