Fuel System

Your car fuel system is an important key to keeping fuel running to the motor giving your car the power and response needed for driving.
Knowing Your Car Fuel System
The car fuel system feeds your engine the gasoline/diesel it needs to run. If anyone of the parts in the system break down your engine will not run. Let's look at the major parts of the fuel system:

Fuel Tank
Basically a holding tank for your fuel. When you fill up at a petrol station the petrol travels down the filler tube and into the tank. In the tank there is a sending unit, which tells the petrol gauge how much petrol is in the tank.

Fuel Pump
On newer cars the fuel pump is usually installed in the fuel tank. Older cars have the fuel pump attached to the engine or on the frame rail between the tank and the engine. If the pump is in the tank or on the frame rail then it is electric and is run by your cars battery. Fuel pumps mounted to the engine use the motion of the engine to pump the fuel.

Fuel Filter
Clean fuel is critical to engine life and performance. Fuel injectors have tiny openings, which clog easily so filtering the fuel is the only way to prevent this. Filters can be before or after the fuel pump, sometimes both.

Fuel Injectors
Most domestic cars after 1986 and earlier foreign cars came from the factory with fuel injection. Instead of a carburetor to mix the fuel and air, a computer controls when the fuel injectors open to let fuel into the engine. This has resulted in lower emissions and better fuel economy. The fuel injector is basically a tiny electric valve, which opens and closes with an electric signal. In the picture below you can see the injectors towards the outer part of the intake. By injecting the fuel close to the cylinder head the fuel stays atomized ( in tiny particles ) so it will burn better when ignited by the spark plug.

Carburetors:
A carburetor takes the fuel and mixes it with air without computer intervention. While simple in operation, they tend to need frequent tuning and rebuilding. This is why most newer cars have done away with carburetors in favor of fuel injection.














Common Car Fuel System Problems:

I would say the most common problem is a clogged fuel filter. Make sure you follow your manufacturers recommendations as to when you should change the fuel filter. This information should be in your owner’s manual. Symptoms include sputtering at high speeds or engine not starting at all. Always check the ignition system first, if that's ok then the next suspect is the fuel filter.

Next most common problem is the fuel pump failing. Most modern electric fuel pumps can be heard when you turn the key on. If you don't hear the pump running and your car will not start, it could be your fuel pump. The first thing a mechanic will check is the relay, which sends power to the pump. If this is operating correctly then the pump will have to be replaced.

Last but not least are dirty injectors. While the fuel filter does a good job of filtering the fuel, it's not perfect. Over time deposits and tiny particles lodge themselves in the injectors. This can clog and injector and prevent it from delivering the fuel the engine needs. It can also cause an injector to stick open and send too much fuel into the engine. A regular addition of fuel system cleaner like STP Injector Cleaner, or Techtron fuel system cleaner can help keep your injectors clean. Most petrol stations, department stores and all automotive parts stores will have a good cleaner available. Add it to your empty tank right before you fill up and it will clean as you drive. I recommend doing this every 3 months to keep your injectors performing like new. Mechanics also offer a cleaning service where they actually disconnect the fuel line and flush cleaner through the engine. This is only necessary when you let your injectors get to a point where they can not be cleaned by a store-bought product. Regular use of a good in-tank cleaner will keep you from having to pay for this service.

Transmission System

Automobile Transmission
The transmission system in a car helps in transmitting mechanical power from the engine to the wheels. Though quite a few types of transmission devices are available all over the world we would be discussing the manual transmission in details as it is the widely used transmission system in India. Automatic transmission will be briefly touched upon as they are slowly making their presence felt in the country.

Manual Transmission
The type of manual transmission which is available in the Indian market is called the Sequential Manual transmission.


This type of transmission doesn’t allow the driver to select any gear at a given point of time. Such a technology will be a boon for the Indian road conditions as cars need sudden acceleration and stopping.



In the type of manual transmission which is available in the country one has to move to the higher gear if one wants to pick up speed and has to do the reverse if he or she needs to slow down.

They come with a driver operated clutch which needs to be depressed while operating the gear stick. The manual transmissions which are available to the country come with four to five gears with one reverse gear. These manual transmissions are referred by their number of forward gears they have i.e. if a car has 5 forward gears they could be referred as 5 speed Manual transmissions.

Advantages of Manual Transmission
Manual Transmission offers a better fuel economy advantage over their automatic counterparts.
It is generally easy to build a robust manual transmission than a strong manual transmission.
Manual transmissions are cheaper than automatic transmissions and require less maintenance than the automatic one
A person driving a car with manual transmission has direct control over the car than a person who is driving the car with automatic transmissions.
A car with manual transmission provides an extra throttle while overtaking since the driver can move to lower gear for more power. Automatic transmission on the other hand has a delayed reaction time.
A car fitted with manual transmission requires a greater degree of control and involvement from the driver than a car with automatic transmissions. Such a system is just right for a place like India where there is a danger lurking everywhere.

Like two sides o a coin there are a few disadvantages associated with cars that use manual transmissions, they are as follows

Driving a car with manual transmission requires greater degree of skill and application, an inexperienced driver could have his hands full while driving as he has to multi task and concentrate on a lot of things simultaneously.
While climbing up a hill, a car with automatic transmission always scores over the one with manual.
In a manual transmission smooth and effective shifting of gears can only be guaranteed by an experienced driver.
A car with manual transmission can't be disabled friendly as it requires a greater degree of control and maneuvering.

Automatic Transmission
Ironically automatic transmission came into the country through two-wheelers rather than their bigger cousin cars. Kinetic Hondathe flagship model from the stable of Kinetic Motors had a decent run with automatic transmission. In this section we will offer you a brief explanation of the automatic transmission system.




The driver doesn't have to change gear ratios manually as gear ratios in the gear box change automatically thus relieving the driver from the added responsibility of changing gears.

However this type of transmission is still to become popular all over the world as they are not as fuel efficient as their manual counterparts.

Though few car models are available in the country with automatic transmission yet the manual transmission is more preferred

Brake System

Brake System

The typical brake system consists of disk brakes in front and either disk or drum brakes in the rear connected by a system of tubes and hoses that link the brake at each wheel to the master cylinder. Other systems that are connected with the brake system include the parking brakes, power brake booster and the anti-lock system.
“When you step on the brake pedal, you are actually pushing against a plunger in the master cylinder which forces hydraulic oil (brake fluid) through a series of tubes and hoses to the braking unit at each wheel.”


“When you step on the brake pedal, you are actually pushing against a plunger in the master cylinder which forces hydraulic oil (brake fluid) through a series of tubes and hoses to the braking unit at each wheel.”


Since hydraulic fluid (or any fluid for that matter) cannot be compressed, pushing fluid through a pipe is just like pushing a steel bar through a pipe. Unlike a steel bar, however, fluid can be directed through many twists and turns on its way to its destination, arriving with the exact same motion and pressure that it started with.




“On a disk brake, the fluid from the master cylinder is forced into a caliper where it presses against a piston. The piston, in-turn, squeezes two brake pads against the disk (rotor) which is attached to the wheel, forcing it to slow down or stop.”
This process is similar to a bicycle brake where two rubber pads rub against the wheel rim creating friction.


“With drum brakes, fluid is forced into the wheel cylinder which pushes the brake shoes out so that the friction linings are pressed against the drum which is attached to the wheel, causing the wheel to stop.”




The main components of a disk brake are the Brake Pads, Rotor, Caliper and Caliper Support.

Drum brakes consist of a backing plate, brake shoes, brake drum, wheel cylinder, return springs and an automatic or self-adjusting system.

Automotive Lessons 4th Quarter "Engine System"

Engine System

There are several engine types which are identified by the number of cylinders and the way the cylinders are laid out. Motor vehicles will have from 3 to 12 cylinders which are arranged in the engine block in several configurations.. In-line engines have their cylinders arranged in a row. 3, 4, 5 and 6 cylinder engines commonly use this arrangement. The "V" arrangement uses two banks of cylinders side-by-side and is commonly used in V-6, V-8, V-10 and V-12 configurations. Flat engines use two opposing banks of cylinders and are less common than the other two designs. They are used in engines from Subaru and Porsche in 4 and 6 cylinder arrangements as well as in the old VW beetles with 4 cylinders. Flat engines are also used in some Ferraris with 12 cylinders


Most engine blocks are made of cast iron or cast aluminum..
Each cylinder contains a piston that travels up and down inside the cylinder bore. All the pistons in the engine are connected through individual connecting rods to a common crankshaft.


The crankshaft is located below the cylinders on an in-line engine, at the base of the V on a V-type engine and between the cylinder banks on a flat engine. As the pistons move up and down, they turn the crankshaft just like your legs pump up and down to turn the crank that is connected to the pedals of a bicycle.




A cylinder head is bolted to the top of each bank of cylinders to seal the individual cylinders and contain the combustion process that takes place inside the cylinder. Most cylinder heads are made of cast aluminum or cast iron. The cylinder head contains at least one intake valve and one exhaust valve for each cylinder. This allows the air-fuel mixture to enter the cylinder and the burned exhaust gas to exit the cylinder. Engines have at least two valves per cylinder, one intake valve and one exhaust valve. Many newer engines are using multiple intake and exhaust valves per cylinder for increased engine power and efficiency. These engines are sometimes named for the number of valves that they have such as "24 Valve V6" which indicates a V-6 engine with four valves per cylinder. Modern engine designs can use anywhere from 2 to 5 valves per cylinder.

The valves are opened and closed by means of a camshaft. A camshaft is a rotating shaft that has individual lobes for each valve. The lobe is a "bump" on one side of the shaft that pushes against a valve lifter moving it up and down. When the lobe pushes against the lifter, the lifter in turn pushes the valve open. When the lobe rotates away from the lifter, the valve is closed by a spring that is attached to the valve. A common configuration is to have one camshaft located in the engine block with the lifters connecting to the valves through a series of linkages. The camshaft must be synchronized with the crankshaft so that the camshaft makes one revolution for every two revolutions of the crankshaft. In most engines, this is done by a "Timing Chain" (similar to a bicycle chain) that connects the camshaft with the crankshaft. Newer engines have the camshaft located in the cylinder head directly over the valves. This design is more efficient but it is more costly to manufacture and requires multiple camshafts on Flat and V-type engines. It also requires much longer timing chains or timing belts which are prone to wear. Some engines have two camshafts on each head, one for the intake valves and one for the exhaust valves. These engines are called Double Overhead Camshaft (D.O.H.C.) Engines while the other type is called Single Overhead Camshaft (S.O.H.C.) Engines. Engines with the camshaft in the block are called Overhead Valve (O.H.V) Engines.
Now when you see "DOHC 24 Valve V6", you'll know what it means.




How an Engine Works
Since the same process occurs in each cylinder, we will take a look at one cylinder to see how the four stroke process works.
The four strokes are Intake, Compression, Power and Exhaust. The piston travels down on the Intake stroke, up on the Compression stroke, down on the Power stroke and up on the Exhaust stroke.




• Intake
As the piston starts down on the Intake stroke, the intake valve opens and the fuel-air mixture is drawn into the cylinder (similar to drawing back the plunger on a hypodermic needle to allow fluid to be drawn into the chamber.)
When the piston reaches the bottom of the intake stroke, the intake valve closes, trapping the air-fuel mixture in the cylinder.
• Compression
The piston moves up and compresses the trapped air fuel mixture that was brought in by the intake stroke. The amount that the mixture is compressed is determined by the compression ratio of the engine. The compression ratio on the average engine is in the range of 8:1 to 10:1.
This means that when the piston reaches the top of the cylinder, the air-fuel mixture is squeezed to about one tenth of its original volume.
• Power
The spark plug fires, igniting the compressed air-fuel mixture which produces a powerful expansion of the vapor. The combustion process pushes the piston down the cylinder with great force turning the crankshaft to provide the power to propel the vehicle. Each piston fires at a different time, determined by the engine firing order. By the time the crankshaft completes two revolutions, each cylinder in the engine will have gone through one power stroke.
• Exhaust
With the piston at the bottom of the cylinder, the exhaust valve opens to allow the burned exhaust gas to be expelled to the exhaust system. Since the cylinder contains so much pressure, when the valve opens, the gas is expelled with a violent force (that is why a vehicle without a muffler sounds so loud.) The piston travels up to the top of the cylinder pushing all the exhaust out before closing the exhaust valve in preparation for starting the four stroke process over again.

Oiling System

Oil is the life-blood of the engine. An engine running without oil will last about as long as a human without blood. Oil is pumped under pressure to all the moving parts of the engine by an oil pump. The oil pump is mounted at the bottom of the engine in the oil pan and is connected by a gear to either the crankshaft or the camshaft. This way, when the engine is turning, the oil pump is pumping.

Engine Cooling

Internal combustion engines must maintain a stable operating temperature, not too hot and not too cold. With the massive amounts of heat that is generated from the combustion process, if the engine did not have a method for cooling itself, it would quickly self-destruct. Major engine parts can warp causing oil and water leaks and the oil will boil and become useless.

Happy New Year Third Year Students!
Well we are back to reality...after so many days of vacation! we have to stick to our bargains and study again...
Here are some reminders for your long test (individual and by pair written test )and practical test...

Pointers to Review:

Automotive Mechanics Concepts
History of Automobiles(Automobile Era)
Cars by Body Structure
Cars by Geographic Region(Country Cars ASIAN,EUROPEAN,AMERICAN)
FORD Road Safety Seminar Topics (handouts/brochure given)
BLOWFATCH
Philippine Standard Road Signs
Types of Tools (Hand,Air,Power)
Car Parts:Interior and Exterior Parts
Tire Changing Procedures

Practical Test: Tire Changing (5 members per Group)

Here are some Notes for your upcoming long test in Automotive Mechanics!Just Download It....Hope it helps....God Bless

Automotive Concepts
Information Handouts Map
Definition of Automobile
Automobile Era
American Cars
European Cars
Japanese Cars
Standard Traffic Signs
BLOWFATCH
Tire Changing Grading Rubrics
How to Read Tire Sidewall Codes

Some topics are for you to research......God Bless You

POINTERS TO REVIEW for COMPUTER 2

Pointers to Review

Lecture: ICT

Types of Network
Network Components
Network Categories

Internet
-History
-Functions
-Components
-Protocols
-Domain Names
-Free Internet Services

Lab: Ms Excel-Spreadsheet Application

History of Spreadsheet
MS-Excel Parts 03/07 Version
Ms Excel Functions
String Functions
-Proper
-Upper
-Lower
-Trim
Numerical Functions
-Sum
-Product
-Quotient
Statistical Functions
-min
-max
-average
Logical Functions
-If
Count Functions
-count
-counta
-countblank
-countif
Date and Time Functions
-Today ()
-Now()

www.vertex42.com For Free Excel Templates
www.techonthenet.com For reference on Excel Functions
http://www.top-windows-tutorials.com/#



Topics For Individual Performance Task (All Topics) Photo Essay Tutorials

1. PC Basics
2. XP Basics
3. Vista Basics
4. Working With Files
5. Make Your PC Faster
6. How to Beat Viruses
7. Smart Internet Surfing

Deadline of Submission of Individual Performance Task

Section 20-November 5
Section 21-November 4
Section 22-November 4
Section 23-November 5
Section 24-November 5

Schedule of Long Test and Practical Exam
Section 20-November 4 WEDNESDAY 8:00 - 9:30 AM HS LABORATORY
Section 21-October 27 TUESDAY Regular Double Period
Section 22-October 28 WEDNESDAY Regular Double Period
Section 23-November 6 FRIDAY 10:00-11:30 AM
Section 24-November 5 Thursday 10:00-11:30 AM

Photo Essay Tutorial Rubrics (Individual Performance Task)