Two Stroke And Four Stroke Engine

Two Stroke And Four Stroke railway locomotiveTo understand the releases between a dickens snap and four bezant locomotive engines, we need to know how the four stroke engine works. In four stroke engine there ar four stagesIntake The speculator travels down the piston chamber bit the ingestion valve is opened to completelyow a form of give notice and seam to enter the combustion chamber.Compression The intake valve is closed and the piston travels back up the cylinder compressing the shoot a lineses. anxious at the stake The spark male plug ignites the compressed gas causing it to explode, which forces the piston down. shake off system The piston rises up the cylinder as the exhaust valve is opened, onlyowing the piston to liberate the chamber to start the process over.Each time the piston rises and fall it turns the crankshaft that is responsible for turning the wheels. This is how provide is converted into forward motion.The spark plug doesnt fire in each rev olution exclusively kinda fires once every other revolution. A camshaft must alternately crumple a rocker arm attached either to the intake or exhaust valve. The rocker arm returns to its closed position according to the proceeding of a spring. The valves must be seated properly in the cylinder head to avoid compression leaks.Now that the four stroke engines apparatus is explained, it is inevitable to learn about the two stroke engine. The chief(prenominal) difference between the two engines is that all four stages in the four stroke engine ar compound into only two phases, one down(prenominal) stroke, and one upward stroke. Intake and exhaust argon both integrated into the compression and combustion movement of the piston, eliminating the need for valves. This is accomplished by an recession and exhaust port in the wall of the combustion chamber itself. instauration the piston travels down the cylinder head, and it applies suction to the port- kindle mixture and exerts it into the cylinder.Compression as the piston travels up to the pourboire of the cylinder head, it applies pressure to the air- discharge mixture from the intake port in the top of the cylinder head, making the air- discharge mixture doctor for igniting by the spark plug.Ignition the spark plug ignites the pressurized air-fuel mixture (otherwise cognise as the compressed air-fuel mixture), or sotimes referred to as the reason stroke.Exhaust as the piston returns back to the top of the cylinder head after the air-fuel mixture has been ignited, the piston pushes the burn down gases out of the cylinder and done the exhaust system. shift Port The port in a two stroke engine that transfers the air-fuel mixture from the bottom of the engine to the top of the cylinder.two-stroke-exhaust.gif 0003EDA6CENGIZ B9A1592CFig2 2-Stroke engineAfter the fuel and air experience a relatively lesser explosion, the piston is driven down to the bottom of the stroke where the exhaust port is un covered. Most of the gases are driven out in this phase. This process is easily seen with an outboard motorboat, straightforward by the multicoloured oil colour slick surrounding the engine, but it happens with all two stroke engines, which is considered one of the disadvantages that makes a designer overlook the utilization of a two stroke engine in their design. And that is be pose this process itself (along with burning oil) creates pollution and fuel efficiency issues.DevelopmentThe idea to build a two-stroke engine goes back to the year 1879. But this engine became a qualitatively good product only after many years, when the German DKW gild accelerated its development. Be buzz off of its disadvantages compared with the four-stroke engine, the two-stroke engine is used practically respectable in a diminished range of capacity, e.g. in small motorcycles considering that the processes involved in the two stroke engine only require the use of a small nitty-gritty of parts and chambers, and that is why they are used in small applications. Formerly the engine was even used to power tiny cars.The briny disadvantage of the two stroke engine would be the loss of fuel and oil (as oil is mixed with fuel, or produced with fresh air to lubricate the piston). And this oil is burnt and sent through the exhaust, as some of the fresh mixture would leave the combustion chamber unburnt. This would basically cause to a greater extent emissions and dirtier exhaust that would damage the catalytic converter.In recent years, the re-appearance of groom fuel guessing (as it already existed in diesel, and 1960s petrol Mercedes), is the main cause of this interest. As direct fuel injection (meaning the fuel injector would be in the combustion chamber such as the spark plug, and would induce the fuel directly in there, as opposed to standard injection where fuel is induced in the intake manifold on top of the valve). This direct injection would limit the fresh mixture loss i n exhaust.The thermal note combustion there is an air pump, called secondary air pump, pumping fresh air into the exhaust when engine is insentient. As on cold starts you have a very rich mixture, meaning raw fuel leaving through the exhaust. The fresh air induced, along with the high temperatures of the exhaust, would cause the fuel in exhaust to burn, this would render the emissions cleaner, and would high temperature up the exhaust faster for the catalytic converter and group O sensors to work (as catalytic converters and oxygen sensors need temperatures around 600 degrees C to operate and clean the emissions).This thermal post combustion would clean the remaining raw fuel or hydrocarbons, and heat the catalytic converters and oxygen sensors, so they always work at optimal temperatures.Problems of the two-stroke engineActually, the two stroke engine should perform double the military operation of a four stroke engine with the same cubic capacity. Although it is just possib le to gain a performance that is about 50% better, but still the reasons are obvious the cylinder cannot be filled up with the same amount of fuel as in the four-stroke engine, because the individual strokes are separated not so clearly which will reduce the amount of space and eventually reduce the capacity for carrying more fuel. If more fuel is induced, it leaves the combustion chamber through the ejection pipe without being burnt. more concepts were developed to provide a better expulsion of the exhaust in way that the fresh gas doesnt leave the combustion chamber. Though all these inventions, the filling of the two-stroke engine is always worse than in the four-stroke engine, which loses fresh fuel only because of the overlap of the valve times (both valves are open for an instant). Beside these performance-technical problems, there are also increasing difficulties with the environment. The fuel mixture of the two-stroke engine often gets shifted with a certain quantity of oil because of the necessary lubrication. Unfortunately the oil gets burnt partly, too, and harmful gases are expulsed by the engine.Two stroke engines already have a lot of advantages over the standard four stroke enginesTwo-stroke engines do not have valves, which simplifies their construction and lowers their weight.Two-stroke engines fire once every revolution, while four-stroke engines fire once every other revolution. This gives two-stroke engines a significant power boost. Two-stroke engines are lighter, and cost less to manufacture. Two-stroke engines have the potential for about twice the power in the same size because there are twice as many power strokes per revolution.Disadvantages of 2 Stroke Engines-Two-stroke engines dont live as long as four-stroke engines. The lack of a dedicated lubrication system nub that the parts of a two-stroke engine wear-out faster. Two-stroke engines require a mix of oil in with the gas to lubricate the crankshaft, connecting rod and cylinder walls. Two-stroke oil can be expensive. Mixing ratio is about 4 ounces per gallon of gas burning about a gallon of oil every 1,000 miles. Two-stroke engines do not use fuel efficiently, yielding fewer miles per gallon. Two-stroke engines produce more pollution from1- The combustion of the oil in the gas. The oil makes all two-stroke engines smoking to some extent, and a badly worn two-stroke engine can blow over more oily smoke.2- Each time a new mix of air/fuel is loaded into the combustion chamber, part of it leaks out through the exhaust port.http//www.deepscience.comhttp//www.whitedoglubes.comhttp//www.atzonline.com/index.phpdo=show/site=a4e/sid=10470432604d6722a19884c564334027/alloc=3/id=829