TDI (engine)

Turbocharged Direct Injection, or TDI, is a name Volkswagen and its partner companies use for a certain type of diesel engine. These engines use a highly-pressurized fuel rail (over 2,000 bar/29,000 PSI) and intercooler to enhance the power gained from turbocharging an engine. These engines could be found in inline three, four, and five configurations, as well as V6, V8, and V10 configurations.

TDI engines have become controversial recently. This is because some TDI engines used a system to under-report their emissions of harmful gases during testing (at the cost of some performance and fuel economy), but were not sold in the emissions-defeating mode, which was a more powerful and efficient fine-tuning of the engine at the cost of more harmful emissions. This meant that the engine could put out up to forty times more nitrogen oxides than was legally allowed.

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