Combustion Engine Types

Autos & TrucksMaintenance

  • Author Aggrey Nzomo
  • Published November 14, 2023
  • Word count 891

The two different types of combustion engines, namely the diesel and the Otto, operate in different ways. The concepts of combustion engines, their classifications notwithstanding, remain very important to every mechanical engineer in the 21st century. The major component of combustion engines is the chamber in which fuel and air burn. Diesel engines are ignited through the compression of fuel and air in the combustion chamber. On the other hand, Otto engines are ignited when the spark plug starts up the burning of air and fuel in the combustion chamber. There is need to understand the workings of the two types of engines in finer detail. There is no doubt that the manner in which the internal combustion engine works is very important to every Mechanical Engineer. The concept of combustion engine has been used in major areas of interest in Mechanical Engineering. These areas include the making of vehicle and water vessel engines. The internal combustion engine is very important in the Mechanical Engineering field.

Engines fitted with internal air and fuel combustions chambers are dubbed as the internal combustion engines. The resultant mechanical energy is obtained when the burning air and fuel particles are pressured by heat energy. According to Ganesan (1995), combustion engines can be grouped into two: the spark ignition and the compression ignition combustion engines. The spark ignition engines work under the principles of the famous Otto cycle. In fact, spark ignition engines have been called Otto engines due to their reliance on the use of Nicolaus Otto’s principle of 1876. On the other hand, compression ignition engines, also called the diesel engines’ operations are informed by the famous Rudolph Diesel cycle principle. Generally, these two types of engines work in more or less similar principles. Rudolph and Otto cycle principles have become the center stage for the designing of engines since their invention to date. The Diesel and Otto engines, that employ Rudolph and Otto cycles principles respectively, are different in the manner in which their air is ignited in the combustion chamber. While in Otto engines the air is ignited by spark plugs fixed on the head of the cylinder the diesel engines’ air is ignited when the optimum pressure in the combustion chamber is reached following the compression under high pressure. Upon injection, the diesel engine starts burning the mixture of air and fuel thus creating mechanical energy needed for moving a motor-device.

Different parts of the diesel and Otto engines serve different purposes.The valves spring serves as the actuater, holding the valves in position during for effective execution of strokes. Wobbling valves do not allow for efficient combustion and may cause smoking and incomplete burning of air and fuel. The in-let valves act as the breathers allowing in fresh air for intake strokes. The exhaust valves take out exhaust air and smoke from rhe combustion chamber. The combustion chambers are also fitted with casing that enclose the oil pana dn the conecting rods. While the cylinder block covers the entire cylinder and the coolant jackets, the cylinder head holds the valves and plugs. Other parts of the combustion chamber include the movable parts like pistons which suck fresh air into the combustion chamber. The connecting rod alters the reciprocating movement of the combustion chamber’s pistons making them rotational thus moving the crunk shaft. Unlike the Otto engine where the spark plug ignites the engine, the diesel engine has fuel injector that springgles fresh fuel into the cylinder which ignites the already pressued and compressed ignition engine.

The compression ignition engine operate in a four-some stroke principle. The suction stroke is the first stroke which brings the oxideizer into the combustion cylinder. At its very initial, the suction stroked starts with the piston at the dead center (TDC). As the piston moves down, the inlet valve opens and the air is drawn into the cylinder as the piston rises up. As the piston reaches the bottom dead center, the stroke comes to an end ushering in the compression stroke. The compression stroke is responsible for increasing pressure in the combustion chamber. As the piston moves from the BDC approaching the TDC, air is compressed at an approximated ratio of 16-20. At this stage, both the inlet and the exhaust valves remain closed. The ignition stage then gets into the third stroke. As the piston gets to the TC, the diesel engine is ignited and comes to live. The diesel is ignited due to the high temperatures and pressure in the combustion chamber.

The findings on the different workings of combustion engines have several implications. Their implications have impacted on the understanding and general practice in mechanical engineering. Mechanical engineers have relied on the inherent differences in the two types of engines, the Diesel and the Otto, to make technical decision. In fact, it is this differences that help mechanical engineers decide which ones to use on different automobiles. Different automobiles are designed for different purposes. Otto engines have been recommended on heavy duty automobiles.

The differences of the two types of engines notwithstanding, their efficiency has stood the test of time. The combustion chambers of the two types of engines are also different. The way they ignited differs significantly. While debates still range on which of the two is most reliable, their differences in terms of ignition have become their selling trademarks.

Aggrey Nzomo is an experienced business development expert with keen interests in environment and renewable energy

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