Other Key Car and Car Engine Components

 

Alternator

 - turns mechanical energy into electrical energy. This energy powers a car's electrics,

from lights to wipers. It also recharges the car battery.

 

 

Mobile Mechanics Stafford district explains 

Alternator & Battery
What’s that squealing noise that I hear for seconds after I start my car in the morning and why do I care?  It’s like this:  The starter motor and alternator are electrical.  The starter motor takes a large amount of electrical energy to produce mechanical energy.  The mechanical energy produced is of course the car’s  motor being turned over so it can start.  Conversely, an alternator takes a large amount of physical energy from the motor driven belt to produce electrical energy.   Initially this electrical energy is used to recharge the battery and replace the electrical energy it took to start the engine.  After the battery is full again the alternator’s task is simply to supply the normally smaller amount of electricity needed to run the ignition, lights, radio, etc. on the running vehicle.  

 

    Here’s the important point:

 

     the more electrical amperage an alternator is putting out,

the more the alternator is resisting being turned.

 

Let’s take an alternator that is capable of putting out 120 amps. It will only be able to put out this

120 amps at about 1350 RPM or higher.  At idle speeds of about 850 RPM it can only produce

55 amps or so.  This is why when you have a loose alternator belt or a defective belt

tensioner, you only hear the squeal when you hit the gas initially after you start the engine,

not with the engine idling.

(When you hit the gas is when the alternator is trying to put out a full 120 amps.)  

Remember it resists being turned in proportion to how much electricity it’s trying to produce.  As soon as the battery is recharged the squeal goes away because the electrical demand is less.

So again, why do I care if the noise goes away within 30 seconds?  

     

    Here’s why:

 

       The carmakers look at how much electricity the car will ever need and then install an alternator that can provide 10-15% more energy than that number just to be safe.  So let’s say that when you’re coming home from Seattle on a dark rainy night, this is your time of maximum electrical need.  At this time of maximum need, to run your defroster, wipers, lights, radio, ignition system, fuel pump, on-board computers, etc.  it takes 88 amps.  This is why your car came equipped with a 100 amp alternator.  If you have a slipping belt that announced itself by that squealing noise that you only heard for the first 30 seconds or so after you started your engine, your alternator will only be able to produce 60-70 amps.  This slight slippage will not be enough to make a squealing noise, but it will result in the battery being chronically undercharged since the battery will supply the rest of the electrical energy needed to get you home.  The slippage also produces heat that can harm the front alternator bearing and damage the drive belt.

The next time you start your car the alternator will have to produce more energy than ever to make up the electrical loss of the slipping belt.  A chronically undercharged battery will also go bad before a fully charged battery, a process called sulphation.  So here is another important point: A battery that is defective or chronically undercharged from a slipping belt causes the alternator to work overtime, and will result in premature alternator failure.  It’s also true that a weak alternator will result in an undercharged battery which can lead to early failure of the battery, which stresses the alternator further.  

 

   The bottom line is this:

      When you hear a belt squeal, get it fixed even if the noise goes away right away. The condition is still hurting the longevity of your battery and alternator. When retensioning a slipping belt, the battery should always be tested. When replacing an alternator, the battery should always be tested. If you’ve been told your battery is weak, replace it even though it may still start your car for a few months.  Your alternator will thank you.  At Mobile Mechanics Stafford district  always make sure all these items are considered and tested when doing electrical work.

for our stafford district customers and Mobile Mechanics Stafford district club members

 

 

   Brakes

 - cars use either drum or disc brakes.

Disc brakes use a calliper to press onto the disc of the wheel in order to

slow the wheel down. Drum brakes work on the same principle however

a drum brake presses against the inside of the drum.

 

 

   Camshaft

 - controls the opening and closing of the intake and exhaust valves.

 

 

   Cooling System

 - car engines produce a lot of heat. This heat needs to be controlled. To do this water is pumped through passages that surround the cylinders and then through the radiators to cool down.

 

   Distributor

 - operates the ignition coil making it spark at exactly the right moment. It also distributes the spark to the right cylinder and at the right time. If the timing is off by a fraction then the engine won't run properly.

 

   Exhaust System

 - once the fuel-air mix has been burnt the remaining gas enters the exhaust system and is expelled from the car. If a catalytic converter is present the exhaust gas passes through it and any unused fuel and other certain chemicals are removed.

 

   Handbrake

 - this is a separate system from the foot brake. As a rule it is mounted on the floor of the car and is connected by a cable to the two rear wheels.

 

   Head Gasket

 - the cylinder head (a block that seals all the tops of the cylinders) and the engine block (which contains the main bodies of the cylinders) are separate components that need to fit seamlessly together.

The head gasket is a piece of metal that sits between them and connects them.

 

   Oil

 - a car engine consists of many moving parts. Oil lubricates these parts and allows them to move smoothly. In most car engines oil is pumped out of the oil pan through a filter that removes any dirt and then is squirted under high pressure onto the bearings and cylinder walls. The oil then trickles down to the sump where the process starts over.

 

    Regulator

 - regulates the amount of energy in the alternator.

 

   Shock Absorbers

 - also known as dampers, are fitted between the car's body and axle in order to prevent excessive rolling and bouncing of the car body during motion.

Suspension System - counteracts the effects of hitting bumps in the road. Without such a system a car would veer of course every time the tyres hit a bump or pothole. The system comprises of springs and shock absorbers. The springs absorb any of the energy released when the tyres roll over a bump and the shock absorbers absorb the energy from the springs. This keeps the main body of the car steady and stable.

 

   Timing Belt

 - a belt connected to both the camshaft and crankshaft ensuring that they work in time with each other.

 

   What is the difference between a Petrol and Diesel Engine?
In petrol engines fuel is mixed with air and then forced into the cylinders where the fuel-air mix is compressed by the pistons and ignited by spark plugs. In a diesel engine the air is compressed before the fuel is added to it. When air is compressed it heats up. This means that when the fuel is added to the compressed air it is very hot and the fuel-air mix ignites automatically. So there are no spark plugs in a diesel engine as pressure is used to ignite the fuel-air mix.