Modern Diesel Engines

Since the advent of the automotive age, diesel-powered vehicles have been considered by many to be noisy, dirty and underpowered. While Americans have viewed the diesel engine as the redheaded stepchild of the powertrain community and perceived diesel fuel as a "strange type of gas," Europe and Asia have long embraced diesel as a powerful and efficient fuel source. Here in the U.S., this alternative to gasoline has persevered by carving a popular niche among commercial trucking and weekend tow vehicles. Now, new developments in diesel engine technologies are creating cleaner, quieter choices for smaller cars, SUVs and luxury sedans without sacrificing performance.


Commercial haulers first turned their attention to diesels for their longer engine life—sometimes two-to-three times that of comparable gas-powered engines—and for their across-the-board superior ability to generate massive amounts of torque. What many may not know is that torque, as opposed to horsepower, is the force that propels a vehicle from a stop up to a comfortable cruising speed. Increased torque in a given vehicle results in faster acceleration and an increased ability to move large mass, i.e. tow heavy loads.

Break It Down
So how does a diesel engine work? Mechanically, diesel engines are very similar to gas engines. Both use a cylinder-enclosed piston that drives a crankshaft, which transfers power to a transmission and so on. And like gas engines, there are two primary types of diesels, two-stroke and four-stroke. Two-stroke engines are generally used for small or very large-scale machines, such as lawnmowers and cargo ships. Four-stroke designs are reserved for midsize machines requiring maximum fuel efficiency, such as automobiles.


So what makes a diesel engine different than a gas engine? The main difference is in the spark, or lack thereof, when it comes to diesel. In gas-powered engines, the fuel is fed into the cylinders and then ignited by a spark from a spark plug. Diesels, on the other hand, spray atomized fuel into the cylinder. As the piston stroke plunges upward, the mixture is compressed. This compression superheats the fuel-soaked air causing it to ignite and drive the piston downward creating energy. The result is a longer lasting, more efficient engine.

Keep It Quiet
Historically, another common byproduct of the diesel engine is increased noise and vibration, something that has kept would-be diesel fans reluctant to cross the powertrain fence. Enter the modern diesel engine. Today's diesels retain all of the long lasting, fuel efficient, high torque qualities they've become known for, while producing less noise and vibration than in years past.