A TDI engine, or Turbocharged Direct Injection engine, is a type of diesel engine that uses turbocharging and direct fuel injection to improve efficiency and performance. This technology allows for better fuel atomization, leading to more complete combustion and reduced emissions. TDI engines are commonly found in vehicles produced by manufacturers like Volkswagen and Audi. The turbocharger in a TDI engine compresses incoming air, increasing its density and allowing more air to enter the combustion chamber. This results in more power without significantly increasing fuel consumption. TDI engines are known for their torque and fuel efficiency, making them popular choices for long-distance driving and heavy-duty applications.