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A petcock is a small shut-off valve used to control the flow of liquid or gas. Historically, petcocks were threaded valves controlled by a butterfly handle;[ citation needed ] modern petcocks are typically ball valves.
Compared to the progressive control of a gate valve a ball valve style petcock's is coarse, confining their use principally to on-off applications.
Most older motorcycles have a three-position fuel petcock valve (known as a "petrol tap" in the UK) mounted on or nearby the fuel tank to control the supply of gasoline: on, off, and reserve.
The reserve position accesses the bottom portion of the fuel tank. Many older motorcycles lacked a fuel gauge, making reliance on a fuel reserve a relatively common experience. Most now have an automatic, vacuum operated petcock (that may include a prime position which bypasses vacuum operation and allows fuel to flow to the carburetor without the engine turning over).
The most common application of a petcock in an automobile is as a drain valve [1] for a radiator. [2]
Historically, petcocks were used on gravity-feed fuel systems found on automobiles. With universal adoption of fuel pumps they have all but disappeared in that application.
Some historic examples of gravity feed systems include the Porsche 356 and early Volkswagens, which have a petcock with off, on, and reserve positions, much like a motorcycle petcock.[ citation needed ]
Petcocks may be used in vehicle heating and cooling systems, such as limousines and tractor trailers. [3]
Many John Deere and other tractors and stationary power units produced from the late 1920s to the early 1940s had compression relief petcocks on the engine block, one per cylinder. These were opened during starting to de-pressurize the cylinders when spinning the flywheel by hand. Once the engine started they were closed and the engine would begin running smoothly.
Petcocks are used to periodically drain water from diesel fuel water separators on some trucks.[ citation needed ]
The large MAN six-cylinder diesel engines used on German U-boats had petcocks that enabled the engineers to verify combustion in each cylinder. Opening one with the engine running would result in a long blue-white flame if the cylinder was firing correctly. The procedure is described in the novel Das Boot and shown in the film version.
A carburetor is a device used by a gasoline internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the Venturi tube in the main metering circuit, though various other components are also used to provide extra fuel or air in specific circumstances.
A two-strokeengine is a type of internal combustion engine that completes a power cycle with two strokes of the piston during one power cycle, this power cycle being completed in one revolution of the crankshaft. A four-stroke engine requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust functions occurring at the same time.
Automobile accessory power can be transferred by several different means. However, it is always ultimately derived from the automobile's internal combustion engine, battery, or other "prime mover" source of energy. The advent of high-powered batteries in hybrid and all-electrical vehicles is shifting the balance of technologies even further in the direction of electrically powered accessories.
Engine braking occurs when the retarding forces within an internal combustion engine are used to slow down a motor vehicle, as opposed to using additional external braking mechanisms such as friction brakes or magnetic brakes.
The Ford Model T used a 177 cu in (2.9 L) sidevalve, reverse-flow cylinder head inline 4-cylinder engine. It was primarily a gasoline engine. It produced 20 hp (14.9 kW) for a top speed of 45 mph (72 km/h). It was built in-unit with the Model T's novel transmission, sharing the same lubricating oil.
The Mitsubishi Astron or 4G5/4D5 engine, is a series of straight-four internal combustion engines first built by Mitsubishi Motors in 1972. Engine displacement ranged from 1.8 to 2.6 litres, making it one of the largest four-cylinder engines of its time.
A flathead engine, also known as a sidevalve engine or valve-in-block engine, is an internal combustion engine with its poppet valves contained within the engine block, instead of in the cylinder head, as in an overhead valve engine.
Manifold vacuum, or engine vacuum in an internal combustion engine is the difference in air pressure between the engine's intake manifold and Earth's atmosphere.
A motorcycle engine is an engine that powers a motorcycle. Motorcycle engines are typically two-stroke or four-stroke internal combustion engines, but other engine types, such as Wankels and electric motors, have been used.
Autogas or LPG is liquefied petroleum gas (LPG) used as a fuel in internal combustion engines in vehicles as well as in stationary applications such as generators. It is a mixture of propane and butane.
A throttle is a mechanism by which fluid flow is managed by constriction or obstruction.
The Detroit Diesel Series 71 is a two-stroke diesel engine series, available in both inline and V configurations, manufactured by Detroit Diesel. The number 71 refers to the nominal displacement per cylinder in cubic inches, a rounding off of 70.93 cu in (1.2 L).
The following outline is provided as an overview of and topical guide to automobiles:
Radiators are heat exchangers used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plants or any similar use of such an engine.
A small engine is the general term for a wide range of small-displacement, low-powered internal combustion engines used to power lawn mowers, generators, concrete mixers and many other machines that require independent power sources. These engines often have simple designs, for example an air-cooled single-cylinder petrol engine with a pull-cord starter, capacitor discharge ignition and a gravity-fed carburettor.
The Kharkiv model V-2 was a Soviet diesel tank V-12 engine, the V angle at 60°, with dual overhead camshafts per bank, four valves per cylinder opened by bucket-style followers and direct fuel injection, features found on modern high-performance diesel engines. Designed at the Kharkiv Locomotive Factory by Konstantin Chelpan and his team, it is found in the BT-7M (BT-8), T-34, KV, IS and IS-10 (T-10) tanks, and by extension, the vehicles based on them, such as the SU-85 and SU-100 tank destroyers based on the T-34 and the ISU-122 and ISU-152 self-propelled guns based on the IS-2. Throughout its production life, output ranged from roughly 450-700 hp.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.
The Ford Model A engine – primarily developed for the popular Ford Model A automobile – was one of the most mass-produced automobile engines of the 1920s and 1930s, widely used in automobiles, trucks, tractors, and a wide variety of other vehicles and machinery.