Turbodiesel

A turbodiesel is a name for a turbocharged Diesel engine. This type of engine was first introduced in a production car in May 1978 in the Mercedes 300SD (series W116, engine OM617.950), only produced for the USA. In Europe its first application was in the Peugeot 604 in early 1979 (model year 1978). Turbocharging is the norm rather than the exception in modern car diesel engines. More modern turbodiesels are the Ford Power Stroke engine series (for Ford F-Series Super Duty trucks, the E-series vans and previously the Excursion SUV) and the Volkswagen and Audi Turbocharged Direct Injection series (for various sedans and SUVs). After a brief lapse between 2000 and 2004 Mercedes reintroduced turbodiesel technology with the introduction of the 2005 E320 CDI. Boasting a 0-100 km/h (0-64mph) time of 6.6 seconds and fuel consumption of 37 mpg, the full year production estimate of 3000 CDIs were ordered within five months. Even more recently, however, Mercedes introduced the BlueTec diesel engine. Offering a 3.0 liter V6, as well as urea injection and particulate filters, the E320 BlueTec has been named the cleanest turbodiesel offered in the United States.

The improvements to power, fuel economy and NVH (Noise, Vibration and Harshness) in both small- and large-capacity turbodiesels over the last decade have spurred their widespread adoption in certain markets, notably in Europe where they (as of 2006) make up over 50% of new car registrations[1]. Turbodiesels are generally considered more flexible for automotive uses than naturally-aspirated diesels, which have strong low-speed torque outputs but lack power at higher speeds. Turbodiesels can be designed to have a more acceptable spread of both power and torque over their speed range or, if being built for commercial use, can be designed to improve either torque or power at a given speed depending on the exact use.

Turbochargers are in many ways more suited to operation in diesel engines. The smaller speed range that Diesel engines work in (between 1000 and 5000 rpm for a private car, and as little as 1000-2500 rpm for a larger unit in a commercial vehicle) mean that the turbocharger has to change speed less, reducing turbo lag and improving efficiency. Diesel engines do not require dump valves (see the turbocharger article for more information) and have lower exhaust temperatures which reduces stress on the turbine blades. The turbodiesel engine can also help with the amount of torque it can give out. Commonly used in trucks, it helps improve the towing capacity of a truck, as well as fuel economy.