REPUBLIC OF PANAMA MARITIME INTERNATIONAL UNIVERSITY OF PANAMA WORK OF ENGLISH DIESEL ENGINES MEMBERS DOMÍNGUEZ, ULISES HOULSTON, LISSETE HINESTROZA, JUAN DATE OF DELIVERY 18- 04- 09
DIESEL ENGINES A diesel engines is a propulsion plant which the heat that is generated by internal combustion a mixture of fuel and air is converted into power
SLOW-, MEDIUM- AND HIGH- SPEED DIESEL ENGINES 1- Slow speed : The slow speed Diesel engines is applied in large vessels whith large engine rooms. Slow- speed Diesel engines consume Heavy Fuel Oil, which is an inexpensive fuel.
2- MEDIUM - SPEED DIESEL ENGINE Are used in large electrical generators, ship propulsion and mechanical drive applications such as large compresors or pumps.
3- HIGH SPEED DIESEL ENGINES Are used in small, highly manoeuvrable vessels. The rated capacity of such an engine is very high, but so is its fuel consumption.
IN- LINE ENGINES AND V- ENGINES Compared to the in- line engine the advantages of the V- engine are obvious: a V- engine requires only one crankshaft and takes up less space. Therefore the engine rooms of limited size, contrary to the in- line engine, which cannot be used in small engine rooms due to its height. Line engine V- engine
TRUNK ENGINES AND CROSSHEAD ENGINES A- Trunk engine: The piston pin and crank pin are directly connected to each other by the connecting rod.
B- crosshead engine : Is taller because of the crosshead and piston rod, which require more space.
TWO- STROKE ENGINES AND FOUR STROKE ENGINES. 1- Two- stroke engine: The two stroke internal combustion engine completes the thermodynamic cycle in two movements of the piston. This increased efficiency is accomplished by using the beginning of the compression stroke and the end of the combustion stroke to simultaneously
2- four- stroke engines: Today internal combustion engines in cars, trucks, motorcycles, aircraft, construction machinery and many others, most commonly use a four stroke engine
THE WORKING OF A TWO- STROKE ENGINE 1- Phase of admission-compression : The piston upwards moves (the butt) from its bottom dead center, in its route leaves t he inlet port open. While the face superior of the piston realises the compression in the cylinder, the face inferior sucks the mixture combustible air through the light . 2- Phase of power-escapes When arriving the piston at its top dead center finalizes the compression and the combustion of the mixture thanks to an electrical spark produced by the spark plug is caused.
THE WORKING OF A FOUR- STROKE ENGINE 1- First time or admission: In this phase the reduction of the piston inhales the mixture combustible air in the motors of caused ignition. 2- Secondly time or compression: When arriving at the end of race inferior, the admission valve is closed, being compressed the gas contained in the camera by the ascent of the piston
3- Third time or explosion: When not being able to arrive at the end of race superior the gas has reached the maximum pressure. In the motors of caused ignition, the inflammation of the mixture jumps the spark in the spark plug causing . 4- Fourth time or escapes: In this phase the piston pushes carefully, in its ascending movement, the gases of the combustion that léale through the escape valve that remains open .
THE VALVE MECHANISM Valves are opened by rocking levers and are mostly closed by springs. The rotating cra nkshaft actuates the camshaft by means of gearwheels or chaindrive. If a pushrod has been inserted between camshaft and rocking lever, the rocking lever will be actuated by this later rod and will open the valve.
REVERSING THE ENGINE The slow speed Diesel engine is mostly a direct reversible- or directing acting- engine. This means that the shaft is directly connected to the engine. In order to go from ahead to astern- or astern to ahead- we must stop the engine first and then reverse it.
THE SHAFT The shaft consists of the propeller shaft, the intermediate shaft and the crankshaft. They are connected to each other by means of flanges. The end of the propeller shaft is conical to make it easier to mount the propeller.