Starting system
The starting system is the heart of the electrical system in your car.the starting system The starting system performs this function by changing energy from the battery to machanical energy in the starting motor.
This motor then transfer the mechanical energy, through gears, to the flywheel on the energy’s crankshaft.During cranking, the flywheel rotates and air-fuel mixture is drawn into the cylinders,compressed, and ignited to start the engine.Most engine requires a cranking speed of about 200r/min,The starting system includes the following components:1.Battery
2.Cable and wires
3.Ignition switch
4.Starter solenoid or relay
5.Starter motor
6.Starter drive and flywheel ring gear
The starting system functions to crank the engine fast enough to allow the engine to start.The starting system and ignition system must work together for good engine starting.
When the driver turns the key switch to START,current flows from the battery through the key switch to the solenoid. The solenoid allows battery current to flow directly from the battery to the starter motor,which in turn cranks the engine.
The automotive battery serves as an energy”bank”.It receives energy from the vehicle’s charging system and stores it untile needed. Then it provides this energy to the many vehicle electrical system on demand.The battery converts electrical energy into chemical energy during charging.It then converts it back into electricity during discharging.
The key switch,or ignition switch, controls the ignition circuit. It also controls the starting system and the power for the instruments and vehicle accessories. Most are steering wheel lock-type switches, which are mounted on the steering column. The starter motor,or starter, is a compact but very powerful direct-current electric motor designed to crank the engine fast enough for it to start. It rotates a small gear called a pinion.A starter drive assembly connects the small pinion gear to the end of the starter motor.The pinion gear meshes with the ring gear on the engine’s flywheel.When the driver turns the key switch, the starter motor drives the pinion gear, which drives the flywheel and cranks the engine,
The gear reduction ratio between the starter motor and the engine must be high enough to provide enough torque to turn engine over at cranking speed. There are approximately 15 to 20 teeth on the flywheel ring gear for every tooth on the drive pinion gear. This mean the armature will rotate approximately 15 to 20 times for every engine revolution. In order to turn the engine over at 100r/min, the armature must rotate at 1500 to 2000r/min.
If the pinion gear remained meshed with the flywheel ring gear at engine speeds above 1000r/min, the armature would be spun at very high speeds. These speeds would damage the armature and the commutator. To avoid this, the starter drive assembly is designed to disengage the pinion gear from the ring gear as soon as the engine begins to operate.
The solenoid is a magnetic switch mounted on top of the starter motor.It has two important functions:it controls the electrical circuit between the battery and starter motor and it shifts the pinion gear in and out of mesh with the ring gear.
All cars equipped with automatic transmission,and most with manual transmissions,have a device to prevent the engine from being started in gear. Without this device, the car would lunge forward or backward if mistakenly started in gear, possibly causing an accident. This device is a neutral safety switch in the starting system circuit. it is mechanically opened when the trasmission shift lever is moved to any position other than Neutral or Park.
Candy www.sinodiesel.com
