|
A starter (also self starter, self, or starter motor) is an electric motor, pneumatic motor, hydraulic motor, an internal-combustion engine in case of very large engines or other device used for rotating an internal-combustion engine so as to initiate the engine's operation under its own power. Engines are feedback systems which once started, rely on the inertia from each cycle to initiate the next cycle. In a four-stroke engine, the third stroke releases energy from the fuel, powering the fourth (exhaust) stroke and also the first two (intake, compression) strokes of the next cycle, as well as powering the engine's external load. To start the first cycle of engine's run session, the first two strokes must be powered in some other way. The starter motor is used for this purpose and is not required once the system starts running. == History == Before the advent of the starter motor, engines were started by various methods including wind-up springs, gunpowder cylinders, and human-powered techniques such as a removable crank handle which engaged the front of the crankshaft, pulling on an airplane propeller, or pulling a cord that was wound around an open-face pulley. The hand-crank method was commonly used to start engines, but it was inconvenient, difficult, and dangerous. The behavior of an engine during starting is not always predictable. The engine can kick back, causing sudden reverse rotation. Many manual starters included a one-directional slip or release provision so that once engine rotation began, the starter would disengage from the engine. In the event of a kickback, the reverse rotation of the engine could suddenly engage the starter, causing the crank to unexpectedly and violently jerk, possibly injuring the operator. For cord-wound starters, a kickback could pull the operator towards the engine or machine, or swing the starter cord and handle at high speed around the starter pulley. Even though cranks had an overrun mechanism, when the engine started, the crank could begin to spin along with the crankshaft and potentially strike the person cranking the engine. Additionally, care had to be taken to retard the spark in order to prevent backfiring; with an advanced spark setting, the engine could ''kick back'' (run in reverse), pulling the crank with it, because the overrun safety mechanism works in one direction only. Although users were advised to cup their fingers and thumb under the crank and pull up, it felt natural for operators to grasp the handle with the fingers on one side, the thumb on the other. Even a simple backfire could result in a broken thumb; it was possible to end up with a broken wrist, or worse. Moreover, increasingly larger engines with higher compression ratios made hand cranking a more physically demanding endeavour. The first electric starter was installed on an Arnold, an adaptation of the Benz Velo, built 1896 in East Peckham, England by electrical engineer H. J. Dowsing. In 1911, Charles F. Kettering, with Henry M. Leland, of Dayton Engineering Laboratories Company (DELCO) invented and filed for the first electric starter in America. (Kettering had replaced the hand crank on NCR's cash registers with an electric motor five years earlier.) One aspect of the invention lay in the realization that a relatively small motor, driven with higher voltage and current than would be feasible for continuous operation, could deliver enough power to crank the engine for starting. At the voltage and current levels required, such a motor would burn out in a few minutes of continuous operation, but not during the few seconds needed to start the engine. The starters were first installed by Cadillac on production models in 1912, with the same system being adopted by Lanchester later that year. These starters also worked as generators once the engine was running, a concept that is now being revived in hybrid vehicles. Although the electric starter motor was to come to dominate the car market, in 1912 there were several competing types of starter,〔 with the Adams, S.C.A.T. and Wolseley cars having direct air starters, and Sunbeam introducing an air starter motor with similar approach to that used for the Delco and Scott-Crossley electrical starter motors (i.e. engaging with a toothed ring on the flywheel). The Star and Adler cars had spring motors (sometimes referred to as clockwork motors), which used the energy stored in a spring driving through a reduction gear. If the car failed to start the starter handle could be used to wind up the spring for a further attempt. The Ford Model T relied on hand cranks until 1919; by 1920 most manufacturers included self-starters, thus ensuring that anyone, regardless of strength or physical handicap, could easily start a car with an internal combustion engine. It was still common for cars to be supplied with starter handles into the 1960s, and this continued much later for some makes (e.g. Citroën 2CV until end of production in 1990). Before Chrysler's 1949 innovation of the key-operated combination ignition-starter switch, the starter was often operated by the driver pressing a button mounted on the floor or dashboard. Some vehicles had a pedal in the floor that manually engaged the starter drive pinion with the flywheel ring gear, then completed the electrical circuit to the starter motor once the pedal reached the end of its travel. Ferguson tractors from the 1940s, including the Ferguson TE20, had an extra position on the gear lever that engaged the starter switch, ensuring safety by preventing the tractors from being started in gear. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Starter (engine)」の詳細全文を読む スポンサード リンク
|