Modern electric automobile self starter motor

An automobile self-starter (commonly "starter motor" or simply "starter") is an electric motor that initiates rotational motion in a car's internal combustion engine before it can power itself. An electric motor uses Electrical energy to produce Mechanical energy. The internal combustion engine is an engine in which the Combustion of Fuel and an Oxidizer (typically air occurs in a confined space called a

History

1920s era self-starter.

Both Otto cycle and Diesel cycle internal-combustion engines require the pistons to be moving before the ignition phase of the cycle. Today Internal combustion engines in cars, Trucks motorcycles aircraft construction machinery and many others most commonly use a four-stroke cycle. The The internal combustion engine is an engine in which the Combustion of Fuel and an Oxidizer (typically air occurs in a confined space called a An ignition system is a system for igniting a fuel-air mixture This means that the engine must be set in motion by an external force before it can power itself. Originally, a hand crank was used to start engines, but it was inconvenient and rather hard work to crank the engine up to speed. It was also highly dangerous.

Even though cranks had an overrun mechanism to prevent it, when the engine started, the crank could begin to spin along with the crankshaft. Additionally, care had to be taken to retard the spark in order to prevent backfiring: with wrong settings, the engine could kick back (run in reverse), pulling the crank with it, because the overrun safety mechanism works in one direction only. Ignition timing in an Internal combustion engine is the process of setting the time that a spark will occur in the combustion chamber (during the Power stroke) relative For other meanings of the term see Backfire. A Back-fire or backfire is an explosion in the Inlet manifold, Carburetor

Although users were advised to cup their fingers 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 endeavor.

While the need was fairly obvious — as early as 1899, Clyde J. Coleman applied for U.S. Patent 745,157  for an electric automobile self-starter — inventing one that actually worked waited until 1911 when Charles F. Kettering of Dayton Electric Laboratories (DELCO) invented and filed for U.S. Patent 1,150,523  for the first useful electric starter. Charles Franklin Kettering ( August 29, 1876 – November 24 or November 25, 1958) was an American inventor and the holder of Delco Electronics Corporation was the automotive Electronics design and manufacturing subsidiary of General Motors based in Kokomo Indiana. The starters were first installed by Cadillac on production models in 1912. Cadillac is a Brand of Luxury vehicles owned by General Motors. These starters also worked as generators once the engine was running, a concept that is now being revived in hybrid vehicles. In Electricity generation, an electrical generator is a device that converts Mechanical energy to Electrical energy, generally using Electromagnetic A hybrid vehicle is a vehicle that uses two or more distinct power sources to propel the vehicle The Model T relied on hand cranks until 1919; by 1920 most manufacturers included self-starters. The Ford Model T (colloquially known as the Tin Lizzie and also the Flivver) was an Automobile produced by Henry Ford 's Ford

The electric starter ensured that anyone could easily start and run an IC car, and made it the design of choice for car buyers from that day to this, even though the internal-combustion engine was not necessarily superior to steam in terms of emissions, range, performance, or fuel efficiency.

Electric starter

Disassembled automobile starter motor

The modern starter motor is either a permanent-magnet or a series- or series-parallel wound direct current electric motor with a solenoid switch (similar to a relay) mounted on it. If two or more circuit components are connected end to end like a daisy chain it is said they are connected in series. Direct current ( DC) is the unidirectional flow of Electric charge. An electric motor uses Electrical energy to produce Mechanical energy. A solenoid is a three-dimensional Coil. In Physics, the term solenoid refers to a loop of wire often wrapped around a Metallic core which A switch is a mechanical device used to connect and disconnect an electric Circuit at will A relay is an electrical Switch that opens and closes under the control of another Electrical circuit. When current from the starting battery is applied to the solenoid, usually through a key-operated switch, it pushes out the drive pinion on the starter driveshaft and meshes the pinion with the ring gear on the flywheel of the engine. Lead-acid batteries, invented in 1859 by French Physicist Gaston Planté, are the oldest type of Rechargeable battery. A key is a device which is used to open a lock. A typical key consist of two parts the blade, which slides into the Keyway of the lock and distinguishes A pinion is usually the smallest Gear in a gear drive train A flywheel is a mechanical device with significant Moment of inertia used as a storage device for Rotational energy.

The solenoid also closes high-current contacts for the starter motor, which begins to turn. Once the engine starts, the key-operated switch is opened, a spring in the solenoid assembly pulls the pinion gear away from the ring gear, and the starter motor stops. The starter's pinion is clutched to its driveshaft through an overrunning sprag clutch which permits the pinion to transmit drive in only one direction. A sprag is a one-way Freewheel clutch used in a number of applications In this manner, drive is transmitted through the pinion to the flywheel ring gear, but if the pinion remains engaged (as for example because the operator fails to release the key as soon as the engine starts), the pinion will spin independently of its driveshaft. This prevents the engine driving the starter, for such backdrive would cause the starter to spin so fast as to fly apart.

This overrunning-clutch pinion arrangement was phased into use beginning in the early 1960s; prior to that time, a Bendix drive was used. The Bendix system places the starter drive pinion on a helically-cut driveshaft. When the starter motor begins turning, the inertia of the drive pinion assembly causes it to ride forward on the helix and thus engage with the ring gear. When the engine starts, backdrive from the ring gear causes the drive pinion to exceed the rotative speed of the starter, at which point the drive pinion is forced back down the helical shaft and thus out of mesh with the ring gear.

An intermediate development between the Bendix drive developed in the 1930s and the overrunning-clutch designs introduced in the 1960s was the Bendix Folo-Thru drive. The standard Bendix drive would disengage from the ring gear as soon as the engine fired, even if it did not continue to run. The Folo-Thru drive contains a latching mechanism and a set of flyweights in the body of the drive unit. When the starter motor begins turning and the drive unit is forced forward on the helical shaft by inertia, it is latched into the engaged position. Only once the drive unit is spun at a speed higher than that attained by the starter motor itself (i. e. , it is backdriven by the running engine) will the flyweights pull radially outward, releasing the latch and permitting the overdriven drive unit to be spun out of engagement. In this manner, unwanted starter disengagement is avoided prior to a successful engine start.

Gear-reduction starters

Chrysler Corporation contributed materially to the modern development of the starter motor. Chrysler LLC is an American Automobile manufacturer that has been producing Automobiles since 1925 In 1962, Chrysler introduced a starter incorporating a geartrain between the motor and the driveshaft. This is the page for mechanical Gears For other uses see Gear (disambiguation For the gear-like device used to drive a roller chain see Sprocket Rolls Royce had introduced a conceptually similar starter in 1946, but Chrysler's was the first volume-production unit. The motor shaft has integrally-cut gear teeth forming a drive gear which mesh with a larger adjacent driven gear to provide a gear reduction ratio of 3. 75:1. This permits the use of a higher-speed, lower-current, lighter and more compact motor assembly while increasing cranking torque. ^[1]. Variants of this starter design were used on most vehicles produced by Chrysler Corporation from 1962 through 1987. The Chrysler starter made a unique, readily identifiable sound when cranking the engine.

Chry_1.5OSGR_Starter.ogg

Hear a Chrysler gear-reduction starter at work

Problems listening to the file? See media help.

This starter formed the design basis for the offset gear reduction starters now employed by about half the vehicles on the road, and the conceptual basis for virtually all of them. Many Japanese automakers phased in gear reduction starters in the 1970's and 1980's. Light aircraft engines also made extensive use of this kind of starter, because its light weight offered an advantage. Those starters not employing offset geartrains like the Chrysler unit generally employ planetary epicyclic geartrains instead. Epicyclic gearing or planetary gearing is a Gear system that consists of one or more outer gears or planet gears revolving about a central or Direct-drive starters are almost entirely obsolete due to their larger size, heavier weight and higher current requirements. Ford also issued a nonstandard starter, a direct-drive "movable pole shoe" design that provided cost reduction rather than electrical or mechanical benefits. Ford Motor Company is an American Multinational corporation and the world's fourth largest automaker based on Worldwide vehicle sales, following This type of starter eliminated the solenoid, replacing it with a movable pole shoe and a separate starter relay. The Ford starter operated as follows:

1. The operator closed the key-operated starting switch.
2. A small electric current flowed through the starter relay coil, closing the contacts and sending a large current to the starter motor assembly.
3. One of the pole shoes, hinged at the front, linked to the starter drive, and spring-loaded away from its normal operating position, swung into position. This moved a pinion gear to engage the flywheel ring gear, and simultaneously closed a pair of heavy-duty contacts supplying current to the starter motor winding.
4. The starter motor cranked the engine until it started. An overrunning clutch in the pinion gear uncoupled the gear from the ring gear.
5. The operator released the key-operated starting switch, cutting power to the starter motor assembly.
6. A spring retracted the pole shoe, and with it, the pinion gear.

This starter was used on Ford vehicles from 1973 through 1990, when a gear-reduction unit conceptually similar to the Chrysler unit replaced it.

Pneumatic starter

Some gas turbine engines and Diesel engines, particularly on trucks, use a pneumatic self-starter. A turbine is a rotary Engine that extracts Energy from a Fluid flow A diesel engine is an Internal combustion engine which operates using the Diesel cycle (named after Dr This article is about the semi-truck For the North American use of the word see Pickup truck. Pneumatics, Pressurized gas to affect mechanical motion Pneumatic power is used in Industry, where it is common to have factory units plumbed for Compressed The system consists of a geared turbine, an air compressor and a pressure tank. A gas compressor is a mechanical device that increases the Pressure of a Gas by reducing its Volume. Compressed air released from the tank is used to spin the turbine, and through a set of reduction gears, engages the ring gear on the flywheel, much like an electric starter would. This is the page for mechanical Gears For other uses see Gear (disambiguation For the gear-like device used to drive a roller chain see Sprocket The engine, once running, powers the compressor to recharge the tank.

Another method, for large diesel engines, uses additional valves in cylinder heads. Compressed air is let in the cylinders so that its pressure pushes pistons down when appropriate; at the upward piston movement, air is discharged through normal exhaust valves.

Since large trucks typically use air brakes, the system does double duty, supplying compressed air to the brake system. Air brakes are used in Trucks Buses trailers, and Semi-trailers. Pneumatic starters have the advantages of delivering high torque, mechanical simplicity and reliability. They eliminate the need for oversized, heavy storage batteries in prime mover electrical systems.

Auxiliary starter engine

A large, high power Diesel engine, such as those used in off-road heavy equipment, may have a small gasoline-powered engine attached to the side as a starter. Engineering vehicles, known by the other terms construction Equipment, earth movers heavy equipment or just plain equipment are machines specifically designed to execute

These were also sometimes called pony engines. On some applications, they shared the same cooling system and oil supply. As the pony engine warmed up, it circulated warm coolant and warm oil in the diesel engine. In addition to making it easier to crank, it improved the service life.

Static-start engine

Another way to provide for shutting off a car's engine when it is stopped, then immediately restarting it when it's time to go, is by employing a static-start engine. Such an engine requires no starter motor, but employs sensors to determine the exact position of each piston, then precisely timing the injection and ignition of fuel to turn over the engine. ^[2]

See also

• Vincent Bendix
• Coffman starter
• Air starter
• Engine control unit

Notes

Patents

• U.S. Patent 745,157  - Clyde J. Coleman
• U.S. Patent 1,050,739  - R. C. Hull
• U.S. Patent 1,464,714  - Arthur Atwater Kent