TDI, or Turbocharged Direct Injection, is a type of diesel engine technology that enhances performance and fuel efficiency. It uses a turbocharger to force more air into the combustion chamber, allowing for more fuel to be burned. This results in increased power output while maintaining lower emissions compared to traditional diesel engines. The direct injection system delivers fuel directly into the combustion chamber at high pressure, improving combustion efficiency. This technology is commonly found in vehicles produced by manufacturers like Volkswagen and Audi, making them popular choices for drivers seeking a balance of power and economy.