Which vehicle is widely credited as the first production car to use a turbocharged diesel engine?

The Mercedes-Benz 300 SD is widely credited as the first production car to use a turbocharged diesel engine.

Mercedes-Benz introduced the 300 SD in 1978 for the North American market. It combined the W116 S-Class body with a five-cylinder diesel engine fitted with a turbocharger. The car was developed partly in response to fuel-economy concerns and increasingly strict emissions requirements.

Turbocharging forced more air into the diesel engine, allowing it to produce more power than a naturally aspirated diesel of similar size. The 300 SD helped demonstrate that diesel technology could be used in a large luxury sedan rather than only in commercial vehicles or economy cars.

The 300 SD is sometimes confused with later turbo-diesel models from Peugeot, Volkswagen, or BMW. Those cars helped popularize diesel power in other markets, but Mercedes-Benz’s North American 300 SD is generally identified as the first production turbocharged diesel passenger car.