Powertrain engineering refers to the development and design of a vehicle's powertrain system, which includes all components that generate power and transmit it to the wheels. This includes the engine, transmission, driveshaft, differential, and axles or wheels themselves. Powertrain engineering involves optimizing these components for performance, efficiency, reliability, and durability while also ensuring they meet emissions standards and are cost-effective. It is a critical aspect of vehicle development as it directly impacts the driving experience, fuel economy, and overall performance of the car or truck.