Turbo Diesel Information
- Turbochargers operate on the same physical principles as the internal combustion engine. Specifically, turbochargers force extra dense air into an engine's combustion chamber where it is mixed with fuel and ignited. Because the air has been forced in by the turbocharger (known as forced induction) rather than being drawn in naturally, its combustion produces a more powerful stroke. This simple addition to the four-stroke engine cycle of intake, compression, ignition, and exhaust results in an engine with a more powerful output and better fuel efficiency.
Turbochargers are powered by the vehicle's exhaust, which spins a turbine before being expelled through the tailpipe. The turbine forces air into the engine, and so the energy that would otherwise be wasted in the form of exhaust is instead harnessed to drive the turbocharger. - The first pioneer of turbo diesel technology was Swiss engineer Alfred Büchi. His plans for turbocharged diesel engines were intended for use on aircraft, where the thin air at high altitudes made forced induction a useful feature. Turbochargers were common on World War I-era planes. By the 1930s, turbo diesel engines were being used in trucks. While turbocharging fell out of style in American-made cars other than a few exceptions, European automakers continued to refine and develop turbo technology. Because of the different compression requirements and air/fuel ratios used with diesel fuel as opposed to gasoline, turbocharging was discovered to be more effective when used on a diesel engine. Turbocharging became briefly popular with Formula 1 racers until excessively powerful engines led the sport's officials to ban the use of turbochargers.
- The primary advantage of a turbo diesel engine over other engine choices is its fuel efficiency and power output. Many turbo diesel engines used in passenger cars and even light trucks are inline four-cylinder engines that produce horsepower and torque ratings comparable to gasoline engines with much larger displacement volumes. Even in cases of turbo diesels that are six- or eight-cylinder engines, the use of a turbocharger allows engineers to use a smaller engine to provide more power. This can be important in designing a car when the space allotted for mounting an engine is limited.
Another important feature of turbo diesel engines is the availability of power at all engine speeds. Instead of the low-end power of most gasoline engines, turbo diesels experience turbo boost at both low and high speeds, thus making the most effective use of their extra power. - Although diesel engines and gasoline engines are very similar, their largest difference makes diesel engines more suitable for turbocharging. This is because of the way ignition occurs. In a gasoline engine, air and fuel are mixed together (either with a carburetor or through fuel injection) and the compressed mixture is then ignited by a spark plug. Diesel engines operate by compressing and heating the air, then injecting the fuel where it is ignited by the heat of the air. This makes turbochargers, which condense air, a natural companion to a diesel engine. Although gasoline engines also experience added power from the extra compression of air, the gains are less dramatic than those seen in a diesel engine of the same size.
- With the energy crisis of the 1970s and the ongoing rise in fuel prices through the 1990s and 2000s, turbochargers have once again ignited interest for their ability to provide more power by using less fuel. Turbo diesel engines are used in a significant percentage of new cars sold in Europe. In the United States, turbo diesel versions of models by automakers such as Mercedes-Benz, Jaguar, Volvo, Saab and Volkswagen are sold alongside their gasoline-powered counterparts.
Trucks are also the target of turbo diesel engines, especially in the United States. Ford's line of Power Stroke V6 and V8 turbo diesel engines are used in some versions of the popular F-Series pickup trucks as well as the E-Series vans.