Kristin Koehler California State University, Bakersfield Lecture 6 July 23 rd, 2013 1
Outline Review (2 and 4 stroke engines) Diesel Engines 2 stroke 4 stroke Benefits of diesel Uses of diesel engines 2
Different cycles Ports vs. Valves Cost Initial Repair Efficiency Pollutants Review 2 Stroke vs. 4 Stroke 3
Diesel Engines History Invented in 1892 by German engineer Rudolf Diesel. Originally designed to provide independent craftsmen and artisans a way to compete with industry. 4
Diesel Engines History The first fully functioning engine that Rudolf Diesel constructed consisted of only one cylinder, 10 feet in length, with a flywheel at the base. 5
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Diesel Engines Compression Ratio The compression ratio is the ratio of volume in the combustion chamber when the piston is at TDC to the ratio in the chamber when the piston is at BDC. Typical gasoline engine 10:1 Pressure-charged gasoline engine 10.5:1 Gasoline racing engine 14:1 Diesel engine 17:1 7
This higher compression ratio allows the diesel engine to contain the thermal energy better, and hence allows the engine to create more power at a higher level of efficiency. 8
Diesel Engines 2 Stroke The two stroke diesel engine, as with the gasoline engine, is much less common than the 4 stroke. It grew in popularity in the 1930 s after Charles F. Kettering improved upon the older 2 stroke model. Currently used in the railroad market and the marine market (submarines, boats, etc.) 9
Diesel Engines (2 Stroke) Stationary Parts Air inlet port the passage that allows air into the combustion chamber Fuel injector sprays a measured amount of fuel into the combustion chamber 10
Diesel Engines (2 Stroke) Moving Parts Camshaft & flywheel Connecting rod Piston Exhaust valve 11
Diesel Engines (2 Stroke) How It Works During the intake stroke air is not only sucked into the chamber by the internal vacuum, but air is also blown into the combustion chamber by a blower attached to the engine just outside of the air intake port. Once the intake port is covered, the compression of the air begins. The air becomes extremely compressed, which in turn creates a great amount of thermal energy. 12
Diesel Engines (2 Stroke) How It Works Once the fuel is ignited, the power stroke begins and the pistol lowers through the chamber. At this point, the exhaust valve is opened. While the piston is below the air intake port, air is blown into the chamber. This also helps scavenge the exhaust from the cylinder. 13
Diesel Engines (2 Stroke) How It Works 14
Diesel Engines 4 Stroke The 4 stroke diesel engine is the most widely used diesel engine. According to the British Society of Motor Manufacturing and Traders, 50% of all vehicles sold in Europe have a diesel engine. Although it is typically thought of as being used in large vehicles, it is used in machinery of all sizes. 15
Diesel Engines (4 Stroke) Stationary Parts Fuel injector sprays fuel into chamber Intake port Exhaust port 16
Diesel Engines (4 Stroke) Moving Parts Crankshaft Connecting Rod Piston Intake (inlet) valve Exhaust valve 17
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Diesel Engines (4 Stroke) 4 Stroke 22
Diesel Engines Turbocharger A turbocharger will increase efficiency and power. It recycles the exhaust and uses it as an extra force during intake. This introduces more oxygen so more fuel can be injected and fuel burn is more complete. 23
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Diesel Engines Fuel Diesel engines require a different type of fuel than the more well known gasoline burning engines. Diesel fuel and gasoline differ chemically and CANNOT be substituted for one another. Using the wrong fuel will cause the engine to cease operation and will require a costly fix. 26
Diesel Engines Fuel Diesel fuel is a variety of petroleum. It is a fossil fuel like gasoline. Diesel fuel is produced from the factional distillation of crude oil. This fractional distillation occurs between 392 and 662 degrees Fahrenheit. It is a hydrocarbon containing carbon chains that typically consist of 8-21 carbon atoms per molecule. 27
Diesel Engines Fuel 28
Gasoline Gasoline is the most well known type of petroleum. It is a fossil fuel, and hence gasoline is another hydrocarbon. Petrol (gasoline) typically consists of 4-12 carbon atoms per molecule. Isooctane 3-ethyltoluene Butane MTBE 29
Diesel Engines Fuel 30
Diesel Engines Size 1, 254, 000 lb. or 627 tons 1, 830 lb or 0.915 tons 31
References http://www.way2science.com/wp-content/uploads/2012/01/dieselengine.gif http://en.wikipedia.org/wiki/two-stroke_diesel_engine http://www.window.state.tx.us/specialrpt/energy/nonrenewable/images/ex hibit4-1.png http://www.docbrown.info/page04/oilproducts/fractionq.jpg http://en.wikipedia.org/wiki/file:gasolinecomp.png 32