The four-stroke cycle of an An internal combustion engine is an engine that is powered by the expansion of hot combustion products of fuel directly acting within an engine. A piston internal combustion engine works by burning hydrocarbon or hydrogen fuel that presses on a piston; and a jet engine works as the hot combustion... internal combustion engine is the cycle most commonly used for automotive and industrial purposes today ( A small variety of cars, the most popular kind of automobile. An automobile is a wheeled vehicle that carries its own engine. Different types of automobile include cars, buses, vans and trucks, with cars being the most popular by far. Older terms include horseless carriage and motor car, with motor... cars and The driver of a car transporter truck prepares to offload Skoda Octavia cars in Cardiff, Wales For further uses of the word truck, see Truck (disambiguation). A truck is a motor vehicle for transporting goods. Unlike automobiles, which usually have a unibody construction, most trucks (with the exception of the... trucks, Generator redirects here. For other uses, see generator (disambiguation) Early 20th century generators An electrical generator is a device that produces electrical energy from a mechanical energy source. The process is known as electricity generation. Developments Before the connection between magnetism and electricity was discovered, generators used electrostatic principles. The... generators, etc). It was invented by Nikolaus August Otto (June 14, 1832 - January 28, 1891) was the coinventor of the internal-combustion engine. As a young man he began experimenting with gas engines and in 1864 joined with two friends to form his own company. The company was named N.A. Otto & Cie., which was... Nikolaus Otto in 1876 is a leap year starting on Saturday. Events January January 31 United States orders all Native Americans to move into reservations. February February 2 - The National League of Professional Baseball Clubs of Major League Baseball is formed. February 14 - Alexander Graham Bell applies for a patent for the telephone... 1876, and is also called the Otto cycle. The four-stroke cycle is more fuel-efficient and clean burning than the The two-stroke cycle of an internal combustion engine differs from the more common four-stroke cycle by having only two strokes (linear movements of the piston) instead of four, although the same four operations (intake, compression, power, exhaust) still occur. Thus, there is a power stroke per piston for... two-stroke cycle, but requires considerably more moving parts and manufacturing expertise and the resulting engine is larger and heavier than a two-stroke engine of comparable power output. The later invented Wankel Engine in Deutsches Museum The Wankel engine is a type of internal combustion engine, invented by Felix Wankel, which uses a rotary piston instead of reciprocating pistons. How it works In the Wankel engine, the four strokes of a typical Otto cycle engine are arranged sequentially around an oval... Wankel engine has four similar phases but does not use a Stroke can mean: In medicine, a cerebrovascular accident (or cerebral accident) A sunstroke In writing, a single line without any break such as stroke in graphics or Chinese characters, see stroke order. A single movement with a tool A single act of striking with a weapon In golf, a single... stroke.

The Otto cycle is characterized by four strokes, or straight movements in a single direction, of a piston + connecting rod In general, a piston is a sliding plug that fits closely inside the bore of a cylinder. Its purpose is either to change the volume enclosed by the cylinder, or to exert a force on a fluid inside the cylinder. Internal combustion engine A piston in an... piston inside a Categories: Stub | Engine technology ... cylinder:

1. intake (induction) stroke
2. compression stroke
3. A power stroke is, in general, the stroke of a cyclic motor which generates force. It is used in describing mechanical engines and molecular motors such as ATP synthase. Many types of motors can be simply describes by first, intake stroke(intake of fuel, e.g. gasoline, ATP, etc.) then... power (ignition) stroke
4. exhaust stroke

The cycle begins at top dead center, when the piston is at its topmost point. On the first downward stroke (intake) of the piston, a mixture of For information on the band, see Fuel (band). Fuel is material with one type of energy which can be transformed into another usable energy. A common example is potential energy being converted into kinetic energy, (as heat and mechanical work). In many cases this is just something that will burn... fuel and This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. If an article link referred you here, you might want to go back and fix it to point directly to the intended page. Air is a name for the mixture... air is drawn into the cylinder through the intake poppet valve A poppet valve is the type of valve system used in most piston engines, used to seal the intake and exhaust ports. The valve is usually a flat disk of metal with a long rod known as the valve stem out one end. The stem is used to... valve or valves. The intake valve then closes, and the following upward stroke (compression) compresses the fuel-air mixture.

The air-fuel mixture is then ignited, usually by a This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. Spark plugs have an insulated wire which is connected with a... spark plug for a Petrol (gasoline in the United States and Canada) is a petroleum-derived liquid mixture consisting primarily of hydrocarbons, used as fuel in internal combustion engines. The term gasoline is the common usage within the oil industry, even within companies that are not American. Often the term mogas (short for motor... gasoline or Otto cycle engine, or by the heat and pressure of compression for a The diesel cycle is the combustion process of a type of internal combustion engine in which the burning of the fuel is triggered not by a spark plug as in the Otto cycle, but rather by the heat generated in compressing the fuel-air mixture. They are used not only... Diesel cycle of The diesel engine is a type of internal combustion engine; more specifically, a compression ignition engine, in which the fuel is ignited by the high temperature of a compressed gas, rather than a separate source of energy (such as a spark plug). It was invented and patented by Rudolf Diesel... compression ignition engine, at approximately the top of the compression stroke. The resulting expansion of burning gases then forces the piston downward for the third stroke (power), and the fourth and final upward stroke (exhaust) evacuates the spent exhaust gases from the cylinder through the then-open exhaust valve or valves.

Valve train

The valves are typically operated by a The camshaft is an apparatus used in piston engines to operate poppet valves. It consists of a cylindrical rod running the length of the cylinder bank with a number of oblong lobes or cams, protruding from it, one for each valve. The cams force the valves open by pressing on... camshaft, which is a rod with a series of oblong protrusions called lobes or cams. As the camshaft rotates, the lobes push against the valves (usually via an intermediate component known as a tappet or lifter, sometimes through a A pushrod or overhead valve (OHV) type piston engine places the camshaft below the pistons and uses pushrods or rods to actuate lifters or tappets above the cylinder head to actuate the valves. This contrasts with an overhead cam (OHC) design which places the camshafts above the cylinder head and... pushrod, the entire chain of parts being known as the valve train), causing them to open at the appropriate time. The valves are spring-loaded, closing after the protruding camshaft lobe releases the valve. Each valve opens only once during the four-stroke cycle; that is, the camshaft makes one rotation for every two rotations of the crankshaft.

Assuming the engine is robust enough in design not to break, the speed and therefore power output of the engine is typically limited by the ability to flow large volumes of air-fuel mixture or exhaust through the valve openings. Therefore a great deal of work goes into designing this part of an engine. Common strategies are to enlarge the valves to take up as much of the cylinder diameter as possible, to lighten the valve train by eliminating parts, to open the valves as far as possible into the cylinder, or to use multiple smaller valves with more total area. Each of these methods has its drawbacks, causing the recent development of engines with computer controlled valve operation to optimize the engine's operation at any speed and load. The illustrations show an engine with A double overhead cam (also called a dual overhead cam, DOHC, or twincam) engine is a type of internal combustion engine where the camshafts that operate the intake and exhaust valves are mounted above the cylinders, and where there are separate camshafts for inlet and exhaust valves. In engines with... Double overhead cams, a standard strategy for many years for increasing the high-speed capability of an engine.

Desmodromic valve timing

In the vast majority of four-stroke engines, the valves are closed simply by return A helical or coil spring. A spring is a flexible elastic object used to store mechanical energy. Springs are commonly made out of steel or brass. Types of spring The most common types of spring are: the helical or coil spring (made by winding a wire around a cylinder) - this... springs. As the rotational speed of the engine increases, the time taken for the spring to pull the valve shut can become significant. The cam follower then fails to follow the closing profile of the cam, changing the timing and therefore the engine performance detrimentally. To reduce this, lighter valves and stronger springs are used, but there is a practical limit to how low the inertial mass of the valve can be reduced, and increasing the strength of the valve return spring greatly increases the already considerable wear on the camshaft.

One solution to this problem is the Desmodromic valves are those which are positively closed by a leverage system, rather than relying on the more conventional springs to close the valves. This is in the context of internal combustion engines. The valves in question are the ones that allow air into the cylinder and (usually different ones... desmodromic valve timing system. This eliminates the valve return spring and uses a mechanical arrangement to both directly open and directly close the valve positively. Much higher engine speeds can then be obtained. Some designs use an additional Epirus (Greek Ήπειρος, Albanian ria), a province in northwestern Greece (a Greek periphery) bounded by West Macedonia and Thessaly to the east, by the Ambracian Gulf and the province of West Greece to the south, the Ionian Sea and the Ionian Islands to the... cam and rocker, others a cam which has a channel milled into its vertical face which the follower runs in (as opposed to following the outside profile only), others a crank arrangement similar to the crankshaft. The drawback of the system is its increased complexity and therefore cost. One manufacturer using this system is Ducati Motor Holding is an Italian motorcycle manufacturer. Ducati motorcycles have long been known for their excellence in design and performance. From the first post-war bicycle-like low-displacement motorbikes Ducati has grown over the years into a racing giant that is consistently competitive in both the racing arena... Ducati, for some of its A motorcycle (or motorbike) is a two-wheeled vehicle powered by an engine. The wheels are in-line, and at higher speed the motorcycle remains upright and stable by virtue of gyroscopic forces; at lower speeds continual readjustment of the steering by the rider gives stability. The rider sits astride... motorcycle engines.

Pneumatic valves

Recent Formula One, abbreviated to F1 and also known as Grand Prix racing, is the highest class of single-seat open-wheel auto racing. It is a worldwide sport, involving an annual World Drivers Championship and World Constructors Championship, and is the most expensive sport in the world, as annual team... Formula 1 engines have resorted to use of pneumatically operated valves to solve the problem of high acceleration of valve opening and closing without excessive cam wear. The cams are omitted entirely, and the opening and shutting of the valves is driven by high pressure air, controlled by computers. With this system, previously unimaginable engine speeds have become routine.

External link

• Animated Engines: Four Stroke Engine (http://www.keveney.com/otto.html)