The Physics of a Diesel Engine
The world we live in is surrounded by diesel engines. They are on the freeways, railways, airways, and are one of the leading electricity producers in the world. They are also becoming more popular in automobiles. These engines are efficient and reliable and they are getting very sophisticated. However, the physics behind these engines has not changed.
By way of definition, courtesy of Diesel Engine
Engineering: [a] diesel engine is an internal combustion engine in which the chemical energy of fuel is transformed into thermal energy of the cylinder charge, in consequence of the self-ignition and combustion of fuel in the engine cylinder after compression of the air charge in the cylinder (p1 Makartchouk).
There are basically two types of diesel engines, two-stroke and four-stroke. In a two-stroke engine the piston is forced from the top of the cylinder by the expanding air fuel mixture. Before the piston reaches the bottom of the cylinder the used mixture, (called exhaust), is forced out of the cylinder by the incoming fresh air. The fresh air relies upon a blower, air induction system, to propel it into the combustion chamber. During this time period the piston begins to travel to the top of the cylinder and compress the fresh air sufficient to raise the temperature in the combustion chamber, (area between the top of the cylinder and the cylinder head at top dead center), to 1000-1200 degrees Fahrenheit (p12 Dagel). The fuel is then injected under pressure into the combustion chamber, the air ignites the fuel and the gases begin to expand finishing one cycle.
A four-stroke engine begins the same way as the two-stroke with the expanding gases pushing the piston downward, called the ...
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...n chamber rises dramatically. The combined fuel and air molecules bounce off one another and since the path of least resistance is the piston, the piston moves downward creating mechanical work.
Applying physics to something in everyday use creates a new appreciation for what actually happens when you step on the accelerator pedal or see a truck pulling 40,000 plus pounds up a steep incline. With even a basic study of physics my worldview has changed. I now look at that cold piece of cast iron sitting in an engine compartment on a molecular level.
Works Cited
Dagel, John F., and Robert N. Brady. Diesel Engine and Fuel System Repair. Ohio: Prentice Hall, 2002.
Kirkpatrick, Larry D., and Gerald F. Wheeler. Physics A World
View. Florida: Harcourt College Publishers, 2001. Makartchouk, Andrei. Diesel Engine Engineering. New York: Marcel Dekker, Inc., 2002.
Diesel mechanics fix and maintain every part associated with the diesel engine. There are many different branches of diesel technology which can include construction and farm equipment, over the road trucks, light duty pickups and stationary engines to name a few. A mechanic must be familiar with major brands of engines like Cummins and Cat. They can perform simple tasks of swapping out a bad component to completely overhauling an engine. The median pay for mechanics is “$42,320 per year or $20.35 per hour (United States).” When overtime hours are reached mechanics receive one and a half times pay for work performed. Negative parts of the job are the amount of overtime hours, the dirtiness of the work, and the cost of tools. Positive parts of the job are overtime pay, hands on, and traveling for work. The job outlook for growth in the diesel field “is projected to grow 9 percent from 2012 to 2022, about as fast as the average for all occupations (United States).” The field of diesel mechanics is still growing today and will continue for a...
This hot gas is pushed out through the back and it makes the rocket move forward. This is using Newton's third law of
Habjanec, Davor. "Detroit Diesel DD15™ Engine." 22 February 2008. Interesting Energy Facts. Article. 6 May 2014.
The diesel engines combustion process is a little different than the typical gasoline engine. A couple main things that diesel engines have that gasoline engines do not are, carburetors and spark plugs. Unlike a gasoline engine, air is first allowed into the cylinder rather than a fuel and air mixture. Once the air is compressed it creates a source of heat, then a mist of fuel is injected to start the combustion process which then creates the energy. Since diesel engines do not have spark plugs they are able to take in larger amount of fuel, this obviously means there will be more power and will guarantee better efficiency. Another thing that is very important is that diesel tends to be a better lubricant than gasoline, being that it is a better lubricant there will be less friction which will generally increase the life of the engine (Woodford). Diesel engines operate at slower speeds than gasoline engines, therefore diesel engines tend to have longer lifespans than gasoline
4. Exhaust: After the Air/Fuel mix has been burnt, the remaining chemicals in the cylinder (water and CO2 for the most part) must be removed so that fresh air can be brought in. As the piston goes back up after combustion, the exhaust valve opens allowing the exhaust gasses to be released. Ideally an engine takes in air (oxygen and nitrogen) and fuel (hydrocarbons) and produces CO2, H2O, and the N2 just passes through.
Stirling engines exhibit the same processes compression, heating, expansion and cooling. Stirling engines operate on a closed thermodynamic cycle. Working fluid undergoes cyclic compression and expansion in separate chambers with varying volume. In a typical Stirling engine, a fixed amount of gas is sealed within the engine, and a temperature difference is applied between two piston cylinders. As heat is applied to the gas in one cylinder, the gas expands and pressure builds. This forces the piston downwards, performing work. The two pistons are linked so as the hot piston moves down, the cold piston moves up by an equal distance. This forces the cooler gas to exchange with the hot gas. The flow passes through the regenerator, where heat is
85% equipments use single-cylinder diesel engines, while the rest use multi-cylinder ones. In the market of multi-cylinder diesel the competition is less intense because of excessive demand. The prospect is much more promising. Longxi has a certain competitive advantage in this market, resulting from its popular product such as SL2100.
In fig 4-21 the flow of the fluid flows through the valve to the right end of the actuating cylinder.It force the piston to the left. Simultaneously on the left of the piston force out the fluid. It goes up through the selector valves and back to the reservoir.
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