Internal Combustion Engine History Applications Parts

By way of contrast, an external combustion engine such as a steam engine, does work when the combustion process heats a separate working fluid, such as water or steam, which then in turn does work.

1 History

The earliest and simplest internal combustion engines seem to have been rockets in the form of fireworks, developed by the Chinese as early as 300 BCE, using gunpowder. They were essentially toys until the 11th century when they evolved into use for weaponry.

The first patent for an internal combustion engine was awarded by the U.S. Patent Office in 1826 to Samuel MoreySamuel Morey ( October 23, 1762 April 17, 1843), American inventor, invented the internal combustion engine and was a pioneer in steamships who accumulated a total of 20 patents. Born in Hebron, Connecticut, he built his first steamboat in 1792 and was gr. This was one of the X-Patents lost in a fire in July 1836Events January Book by Maria Monk claims that she was sexually exploited in a Canadian convent February 3 United States Whig Party holds its first convention in Albany, New York. February 23 The siege of the Alamo begins in San Antonio, Texas. February 24 and not recovered until 20042004 is a leap year starting on Thursday (the link is to a full 2004 calendar), and has also been designated the: International Year of Rice International Year to Commemorate the Struggle against Slavery and its Abolition Elections are to be held in 73 co.

In 1858Events January 14 Felice Orsini and his accomplices fail to assassinate Napoleon III in Paris but their bombs kill 156 bystanders. Because of the involvement of French emigres living in Britain, there is a brief anti-British feeling in France but the empe, Jean Lenoir invented the first practical internal combustion engine. It relied upon coal gas that was sucked into the cylinder at the beginning of each stroke and then ignited to push the piston to the other end of the cylinder. This process was then repeated at the other end of the cylinder making the engine double-acting .

In 1867Events January 8 African-American men granted the right to vote in the District of Columbia January 11 Benito Juarez becomes Mexican president again January 30 Emperor Komei of Japan dies. Crown Prince Mutsuhito is expected to become the next Emperor of J Nikolaus Otto built the first four-stroke internal combustion engine. This engine proved more efficient than Lenoir's design and was successfully marketed for industrial purposes. The design was later improved by Gottlieb Daimler who focused on making the technology practical for use in automobiles most notably by incorporating a gasoline carburettor. In 1890 Wilhelm Maybach built the first four-cylinder internal-combustion engine. Both Maybach and Daimler were originally employees of Otto's company but had left in 1882 to form their own company.

Over the same time period the two-stroke internal combustion engine was being perfected, which had been invented in 1867 by Sir Dougald Clerk . The design was later simplified by Joseph Day in 1891.

In 1930 Sir Frank Whittle patented the use of a gas turbine for jet propulsion. The first successful use of this engine was in April, 1937. Ernst Heinkel Aircraft flew the first flight in 1939 of a gas turbine jet, the HE178.

2 Applications

Internal combustion engines are most commonly used for mobile propulsion systems. They appear in almost all cars, motorbikes, many boats, and in a wide variety of aircraft and locomotives. In jet aircraft and large ships, they appear mostly in the form of gas turbines. They are also be used for electric generators and by industry.

For many non-mobile applications, an electric motor is a competitive alternative. In the future electric motors may also become competitive for most mobile applications. However, at the moment the high cost and weight of batteries and the lack of affordable onboard electric generators such as fuel cells restrict their use.

3 Parts

An illustration of several key components in a typical four-stroke engine

The parts of an engine vary depending on the engine's type. For a four-stroke engine, key parts of the engine include the crankshaft, one or more camshafts (magenta and blue) and valves. For a two-stroke engine, there may simply be an exhaust outlet and fuel inlet instead of a valve system.

In both types of engines, there are one or more cylinders (grey and green) and for each cylinder there is a spark plug (darker-grey), a piston (yellow) and a crank (purple). A single sweep of the cylinder by the piston in an upward or downward motion is known as a stroke and the downward stroke that occurs directly after the air-fuel mix in the cylinder is ignited is known as a power stroke.

A Wankel rotary engine has a triangular rotor that orbits in an epitroichoid al (figure 8 shape) chamber around an eccentric shaft. The four phases of operation (intake, compression, power, exhaust) take place in separate locations, instead of one single location as in a reciprocating engine.

4 Operation

All internal combustion engines depend on the exothermic chemical process of combustion: the reaction of a fuel, typically with air, although other oxidisers such as nitrous oxide may be employed. See also stoichiometry.

The most common fuels in use today are made up of hydrocarbons and are derived from petroleum. These include the fuels known as diesel, gasoline and liquified petroleum gas. Some have theorized that in the future hydrogen might hydrogen. The advantage of hydrogen is that its combustion produces only water. This is unlike the combustion of hydrocarbons which also produces carbon dioxide, a major cause of global warming.

All internal combustion engines must have a means of ignition to promote combustion. Most engines use either an electrical or a compression heating ignition system. Electrical ignition systems generally rely on a lead-acid battery and an induction coil to provide a high voltage electrical spark to ignite the air-fuel mix in the engine's cylinders. This battery can be recharged during operation using an alternator driven by the engine. Compression heating ignition systems ( Diesel engine]s) rely on the heat created in the air by compression in the engine's cylinders to ignite the fuel when it is injected.

Once successfully ignited and burnt, the combustion products (hot Diesel engine]s) rely on the heat created in the air by compression in the engine's cylinders to ignite the fuel when it is injected.

Once successfully ignited and burnt, the combustion products (hot gases) have more available energy than the original compressed fuel/air mixture (which had higher chemical energy). The available energy is manifested as high temperature and pressure which can be translated into work by the engine. In a reciprocating engine, the high pressure product gases inside the cylinders drive the engine's pistons.

Once the available energy has been removed the remaining hot gases are vented (often by opening a valve or exposing the exhaust outlet) and this allows the piston to return to its previous position (Top Dead Center - TDC). The piston can then proceed to the next phase of its cycle (which varies between engines). Any heat not translated into work is a waste product and is removed from the engine either by an air or liquid cooling system.

5 Classification

There is a wide range of internal combustion engines corresponding to their many varied applications. Likewise there is a wide range of ways to classify internal-combustion engines, some of which are listed below.

5.1 Principles of operation

Reciprocating:

Rotary:

Wankel engine

Continuous Combustion:

5.2 Engine cycle

Engines based on the two-stroke cycle use two strokes (one up, one down) for every power stroke and are used in lawnmowers, mopeds, outboard motors and some motorcycles. They are generally louder, less efficient, more polluting, and smaller than their four-stroke counterparts. Engines based on the four-stroke cycle or Otto cycle have one power stroke for every four strokes (up-down-up-down) and are used in cars, larger boats and larger aircrafts. They are generally quieter, more efficient and larger than their two-stroke counterparts. There are a number of variations of these cycles, most notably the Atkinson and Miller cycles. Diesel engines use a four-stroke cycle, but with a compression heating ignition system it is possible to talk separately about a diesel cycle. The Wankel engine operates with the same separation of phases as the four-stroke engine, but would more properly be called a four-phase engine, since there are no reciprocating strokes and the phases occur in separate locations in the engine.

5.3 Fuel type

Diesel engines are generally heavier, noisier and more powerful at lower speeds than gasoline engines. They are also more fuel-efficient in some circumstances and are used in heavy road-vehicles, ships and some locomotives. Gasoline engines are used in most other road-vehicles including most cars, motorcycles and mopeds. Both gasoline and diesel engines produce significant emissions. There are also engines that run on hydrogen, methanol, ethanol, liquefied petroleum gas (LPG) and biodiesel.

5.4 Cylinders

Internal combustion engines can contain any number of cylinders with numbers between one and twelve being common, though as many as 28 have been used. More cylinders result in greater torque but obviously larger engines and greater fuel consumption.

Most car engines have four to eight cylinders, with some high performance cars having ten or twelve, and some very small cars and trucks having two or three. In previous years some quite large cars, such as the DKW and Saab 92, had two cylinder, two stroke engines.
Radial aircraft engines, now obsolete, had from five to 28 cylinders. A row contains an odd number of cylinders, so an even number indicates a two- or four-row engine.
Motor cycles commonly have from one to four cylinders, with a few high performance models having six.
Small appliances such as chainsaws and domestic lawn mowers most commonly have one cylinder, although two-cylinder chainsaws exist.

5.5 Ignition system

Internal combustion engines can be classified by their ignition system. Today most engines use an electrical or compression heating system for ignition. However outside flame and hot-tube systems have been used historically.

5.6 Engine configuration

Internal combustion engines can be classified by their configuration which affects their physical size and smoothness (with smoother engines producing less vibrations). Common configurations include the straight or inline configuration, the more compact V configuration and the wider but smoother flat or boxer configuration. Aircraft engines can also adopt a radial configuration which allows more effective cooling. More unusual configurations, such as " H", "X", or " W" have also been used.

Multiple-crankshaft configurations do not necessarily need a cylinder head at all, but can instead have a piston at each end of the cylinder, called an opposed piston design. This design was used in the Junkers Jumo 205 diesel aircraft engine, using two crankshafts, one at either end of a single bank of cylinders, and most remarkably in the Napier Deltic diesel engines, which used three crankshafts to serve three banks of double-ended cylinders arranged in an equilateral triangle with the crankshafts at the corners. It was also used in single-bank locomotive engines, and continues to be used for marine engines, both for propulsion and for auxiliary generators. The Gnome Rotary engine, used in several early aircraft, had a stationary crankshaft and a bank of radially arranged cylinders rotating around it. Technically this is a "rotating" engine, to distinguish it from Wankel "rotary" engines.

5.7 Engine capacity

An engine's capacity is the displacement or swept volume by the pistons of the engine. It is generally measured in litres or cubic inches for larger engines and cubic centimetres (abbreviated to cc's) for smaller engines. Engines with greater capacities are usually more powerful and provide greater torque at lower rpms but also consume more fuel.

Apart from designing an engine with more cylinders, there are two ways to increase an engine's capacity. The first is to lengthen the stroke and the second is to increase the piston's diameter. In either case, it may be necessary to make further adjustments to the fuel intake of the engine to ensure optimal performance.

An engine's quoted capacity can be more a matter of marketing than of engineering. The Morris Minor 1000, the Morris 1100, and the Austin-Healey Sprite Mark II all had engines of the same stroke and bore according to their specifications, and were from the same maker. However the engine capacities were quoted as 1000cc, 1100cc and 1098cc respectively in the sales literature and on the vehicle badges.

5.8 Other classifications

All internal combustion engines are heat engines and thus have a physical upper bound on their efficiency achieved only by the theoretical Carnot heat engine. A few internal-combustion engines that use rotary instead of linear piston motion are known as Wankel engines, Orbital engines or Quasiturbines.

6 Performance

The chief measure of a reciprocating internal combustion engine is the turning force or torque it provides for any given speed. Here the speed of an engine means the number of revolutions per minute the engine makes. The SI unit for angular velocity is radians per second and a conversion from revolutions per minute to radians per second is found using the formula:

where is the engine's speed in radians per second and is the engine's speed in revolutions per minute

The engine's torque and speed are then related by the equation:

where is the engine's torque in Newton metres, is the rotational inertia attached to the engine and is the speed of the engine in radians per second

If a solid cylinder were attached to the engine, the rotational inertia of that cylinder would simply be a function of its radius and mass. Using this fact and the above equation, it is possible to build a device called a dynamometer to measure an engine's torque.

After measuring an engine's torque, the engine's power can be found using the equation:

where is the engine's power in watts, is the engine's torque in Newton metres and is the speed of the engine in radians per second.

Using a simple conversion this value for power may also expressed in horsepower.

Power is useful from an engineering perspective in that it provides the rate of mechanical work possible. However motoring enthusiasts will tell you that torque is what the driver "feels". This is because under identical load conditions the torque is proportional to acceleration. It is possible to increase the performance of an engine through engine tuning. Although engine performance is important in most systems, engineers must balance it with economic considerations, physical weight limitations, vibrational requirements, and fuel efficiency.

It is also important to note that the torque of an engine can be effectively increased by sacrificing speed through the use of gears so the power output ideally remains the same over a wider range of output speeds. (In reality some power is lost due to friction between the gears.)

Some indication of an engine's performance is given by graphing the engine's torque against its speed on a dynamometer (dyno) graph. A sample dyno graph is included here. It should be noted that an engine designer can place the peak of the torque curve more or less anywhere they choose, depending on the engine's application. A broad, flat torque curve is ideal. Other applications such as engines to drive aircraft, boats, pumps, generators, etc often have maximum torque at a much lower speed, or a sharper curve so that power is maximised over a narrower range of operating speeds. The profile of the cylinder is largely responsible for the overall shape of the power curve.

7 External link:

How Internal Combustion Works - with animation

Piston engines

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