Rope start (also called pull start[ citation needed ] or rewind start[ citation needed ]) is a method of starting an internal combustion engine, usually on small machines, such as lawn mowers, chainsaws, grass trimmers, ultralight aircraft, small outboard motors and portable engine-generators. Also used on some small vehicles such as small go-karts, minibikes, and small ATVs.
This starter mechanism comprises a rope, with a grip at the end, moulded rope reels and a spring. The rope is coiled within a reel which is held under spring tension within an outer reel. This reel assembly is in contact with one end of the crankshaft through a ratcheting mechanism (specifically, a freewheel clutch). When the rope's grip is pulled, the rope uncoils, tensions the spring, engages the clutch and turns the crankshaft, spinning it to crank or start the engine before the end of the pull stroke. The running of the engine then disengages the clutch. When the user releases the grip, the spring operated reel retracts the rope, setting it up for the next start operation. This recoiling of the rope (as opposed to the rope detaching) gives the recoil starter its name. (Should the engine fail to start, the stopping of the rope pull also disengages the clutch so the rope can be recoiled). This was created by Jacobsen Manufacturing in 1928.[ citation needed ]
A reel connected to the crankshaft has a notch in it to put a rope through. The rope is wound around the reel and pulled, starting the engine, but once the end of the pull is reached, it comes free, leaving a loose rope in the person's hand. If the engine fails to start on the first pull, the operator has to re-wind it by hand. [ citation needed ]
A number of features are labelled by manufacturers as "easy start," such as the presence of a primer bulb, an additional elastic/spring element between the starter rope and the crankshaft, a decompression release, or simply an engine which the manufacturer contends is easy to start. [1]
A compression release feature, found on many modern engines and especially larger 2-strokes, is a valve in the combustion chamber which can be held open while the rope is being pulled, avoiding the need to overcome compression while imparting enough angular momentum for the engine to continue. Once the engine fires on its own and creates a sufficient over-pressure, the mechanism is deactivated so the engine can develop enough compression to run normally. [2] [3] Compression release valves may, depending on the design, either be manually opened by the operator or be automatically opened when the choke is engaged or whenever the engine is not running. [3]
A clutch is a mechanical device that allows the output shaft to be disconnected from the rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does the work.
A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common features of all types. The main types are: the internal combustion engine, used extensively in motor vehicles; the steam engine, the mainstay of the Industrial Revolution; and the Stirling engine for niche applications. Internal combustion engines are further classified in two ways: either a spark-ignition (SI) engine, where the spark plug initiates the combustion; or a compression-ignition (CI) engine, where the air within the cylinder is compressed, thus heating it, so that the heated air ignites fuel that is injected then or earlier.
In engineering, the Miller cycle is a thermodynamic cycle used in a type of internal combustion engine. The Miller cycle was patented by Ralph Miller, an American engineer, U.S. patent 2,817,322 dated Dec 24, 1957. The engine may be two- or four-stroke and may be run on diesel fuel, gases, or dual fuel. It uses a supercharger to offset the performance loss of the Atkinson cycle.
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.
A starter is a device used to rotate (crank) an internal-combustion engine so as to initiate the engine's operation under its own power. Starters can be electric, pneumatic, or hydraulic. The starter can also be another internal-combustion engine in the case, for instance, of very large engines, or diesel engines in agricultural or excavation applications.
A four-strokeengine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed:
Field-Marshall was a brand of farm tractor which was manufactured by Marshall, Sons & Co. of Gainsborough, Lincolnshire in the United Kingdom.
The Ford 335 engine family was a group of engines built by the Ford Motor Company between 1969 and 1982. The "335" designation reflected Ford management's decision to produce an engine of that size with room for expansion during its development. This engine family began production in late 1969 with a 351 cu in (5.8 L) engine, commonly called the 351C. It later expanded to include a 400 cu in (6.6 L) engine which used a taller version of the engine block, commonly referred to as a tall deck engine block, a 351 cu in (5.8 L) tall deck variant, called the 351M, and a 302 cu in (4.9 L) engine which was exclusive to Australia.
In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An overdrive is sometimes mistakenly called a freewheel, but is otherwise unrelated.
A compression release engine brake, compression brake, or decompression brake, frequently called a Jacobs brake or Jake Brake, is an engine braking mechanism installed on some diesel engines. When activated, it opens exhaust valves to the cylinders, right before the compression stroke ends, releasing the compressed gas trapped in the cylinders, and slowing the vehicle.
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.
Kick start is a method of starting an internal combustion engine by pushing a ratcheting lever with one's foot. Kick start mechanisms were almost universally a part of motorcycle engines before the mid-1970s, and were phased out of production over the next twenty years or so as electric starters became standard equipment. There are still some motorcycles produced that have both kick and electric starters.
Chainsaws and chainsaw operations have specific risk control methods.
Variable compression ratio (VCR) is a technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. This is done to increase fuel efficiency while under varying loads. Variable compression engines allow the volume above the piston at top dead centre to be changed. Higher loads require lower ratios to increase power, while lower loads need higher ratios to increase efficiency, i.e. to lower fuel consumption. For automotive use this needs to be done as the engine is running in response to the load and driving demands. The 2019 Infiniti QX50 is the first commercially available vehicle that uses a variable compression ratio engine.
A compression release mechanism works to ease the starting of internal combustion engines by allowing them to spin up to starting speed without having to work against the pumping action of the pistons. It does this through a release valve that is incorporated within the cylinder head that vents the cylinder pressure to the outside atmosphere until the engine has sufficient momentum to overcome it. At that point the valve closes and the ignition is engaged.
Internal combustion engines come in a wide variety of types, but have certain family resemblances, and thus share many common types of components.
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.
Many variations of aircraft engine starting have been used since the Wright brothers made their first powered flight in 1903. The methods used have been designed for weight saving, simplicity of operation and reliability. Early piston engines were started by hand. Geared hand starting, electrical and cartridge-operated systems for larger engines were developed between the First and Second World Wars.
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.
Gliding is an energy-efficient driving mode achieved by turning off the internal combustion engine while the vehicle is still moving in order to save fuel. This is differentiated from coasting, which means running the vehicle in idle mode by disengaging the engine from the wheels, either by disengaging the clutch or setting the transmission or gearbox to neutral position. Gliding and coasting use the accelerated kinetic energy reserve stored in the vehicles mass, i.e. inertia, to keep the vehicle moving. This energy, however, is being lost due to forces that resist movement, such as air-drag, rolling resistance and gravity. The functionality, being an integral concept of hybrid electric vehicles, is performed automatically by the engine controller. For vehicles with a conventional internal combustion engine, coasting can be performed manually; gliding requires having a gear box. Manual gliding or coasting is illegal in some states. An extra button to stop the engine was shown in 1979 on International Motor Show Germany, but never became a feature in mass production of any vehicle. In 1980 research was made on the IRVW II. A so-called eClutch uses an actuator to disengage the clutch when the driver releases the accelerator.