Diesel Engine

Abstract: In the 1890s, Rudolf Diesel invented an efficient, compression ignition, internal combustion engine that bears his name. Early diesel engines were large and operated at low speeds due to the limitations of their compressed air-assisted fuel injection systems. In its early years, the diesel engine was competing with another heavy fuel oil engine concept—the hot-bulb engine invented by Akroyd-Stuart. High-speed diesel engines were introduced in the 1920s for commercial vehicle applications and in the 1930s for passenger cars. it’s no secret that the majority of Americans are more accustomed to gasoline engines than diesels. Statistics gathered by R.L. Polk confirm this, as just 2.8 percent of all registered passenger vehicles (cars, SUV’s, pickup trucks, and vans) ran on number 2 diesel fuel in 2013. To be sure, most folks in the U.S. expect to find spark plugs or coil packs when they pop the hood, not turbochargers and injection pumps (two very key elements on nearly every diesel engine you’ll come across, hence the term “turbodiesel”). In order to gain an understanding of the differences between diesel and gasoline engines, we’ll begin with all of the similarities shared between the two. The type of fuel burned by either power plant doesn’t change anything in relation to the engine’s general makeup (i.e. a crankshaft spinning, connecting rods and pistons moving up and down, air being pumped in, and exhaust being routed out). In fact, the same basic architecture is very much the same. But what goes on in-cylinder in a diesel is vastly different from what you’ll find in its gas-powered counterparts. The easiest way to explain the difference between gasoline and diesel engines is with “air” and “fuel.” In a gasoline engine, airflow is everything. You’re throttling air. A diesel mill is the polar opposite. It works on the premise of throttling the amount of fuel being injected—the air simply follows suit. Therefore there is no need to throttle the incoming air. To that end, there is also no vacuum created within a diesel engine.