Diesel Cycle in Internal Combustion Engines

Summary:

The Diesel Cycle is an air-standard cycle used in Compression-Ignition Engines. Rudolf Diesel developed it and utilized high compression to ignite fuel. Unlike the Otto Cycle, it does not use a spark plug but injects and ignites fuel with compressed air. The cycle involves four processes: suction stroke, compression stroke, expansion stroke (power stroke), and exhaust stroke.

A Compression-Ignition Engine has a fuel pump, atomizer (injector), and different fuel injection systems like an Air injection System and an Airless (Solid) injection System. The compression ratio in Diesel Engines is higher than in Spark-Ignition Engines, resulting in lower air-standard cycle efficiency for Diesel Engines.

Overall, the Diesel Cycle’s main feature is its Compression-Ignition operation, distinguishing it from the spark-ignition operation in Otto Engines.

Excerpt:

Diesel Cycle in Internal Combustion Engines

A. WHAT IS A DIESEL CYCLE?

A Diesel Cycle is an air-standard cycle that uses constant pressure head addition or isobaric heat addition. In 1898, a German inventor and mechanical engineer, Rudolf Diesel, developed an engine with a high compression ratio to ignite the fuel. The fuel was injected in small amounts once the piston reached TDC and ignited by the hot compressed air. Both four-stroke and two-stroke have been incorporated onto Diesel Engines.

The Diesel Cycle is the ideal air-standard cycle for Diesel Engines, commonly known as Compression-Ignition Engine (sometimes called constant pressure cycle or pressure cycle). Unlike the Otto Cycle, this does not use a spark plug to produce heat in the system; it doesn’t have a carburettor as well since the combustion of the Diesel Cycle requires the air to enter the combustion chamber alone where an atomizer is used to spray small amounts of Diesel in an atom-like size before the piston reaches TDC. The atomized Diesel particles, air, and piston compression are enough to produce heat, which is why it is called Compression-Ignition Engine.

Diesel Cycle and Otto Cycle:

Now, what will happen if we switch the two fuels and have Petrol/Gas be sprayed and atomized in a Diesel Cycle, and have Diesel be mixed with air in the carburetor and ignited by a spark plug?