4849

Ayob aghazi 4849

Monday, 26 November 2012

Costomer bad exprince

TTEC4849 Business Practice and Vehicle Safety

Customer Story of a Bad Experience

Instructions:

Divide up into small groups. Read the following story, and

discuss the following questions in your small groups. Then write your answers

in the space provided.

This is a true story.

The year was about 1958, in California, before there were strong consumer

laws. Don Higgins owned a laundry and dry cleaning business, in which he

used one of the new Volkswagen bus trade vans for his deliveries. He would

pick up dirty clothes from businesses (like restaurants and auto repair shops),

clean them and deliver them back. He liked his Volkswagen van: it had lots of

space to hang the clothes and it got good fuel economy. Up until recently, it

had been very reliable. But lately the engine wasn’t running very well. The

engine was regularly missing and had low power.

So in the morning, Don took his van to his local auto repair shop. He told them

it needed fixing, maybe just a tune up, and he got a ride back to his cleaning

business. Then in mid-afternoon, he went back to pick up his van.

To his surprise, the van wasn’t ready. If fact, the repair shop owner showed

Don the engine that was now out of the van. The exhaust valve for number 3

cylinder was burnt, causing the poor running engine and lack of power. The

shop owner said he could have the engine fixed and back in the van in 3 or 4

days. And the bill would be about $400.00. (In 1958, this was a lot of money.

Don’s monthly mortgage on his house was only about $120.00 per month.)

Don was very upset. He was so upset that I (Steve McAfee) heard about this

as the little boy who lived next door to Don.

Discussion Questions:

1. From Don’s point of view, what was wrong here? What did the shop do

wrong that upset Don so much. (After all, they were fixing his van.)

Don was so upset becasue they didnt fix the car in the time they had , they waited until don came the following afternoon and they told him then, they said it would take 3-4 days to fix it, don worked with his car to deliver his goods but he cannot do this because his car will be in repair for 3-4 days he can not work.

2. From the repair shop owner’s point of view, what was wrong with Don

getting upset at them? What did they do right or wrong?

The repair shop owner thought that he fixes his car he will tell Don how much it will cost

3. What should have been done in this circumstance? If you were Don, what

would you have wanted to be done?

I would want the repair owner to wait until i coem to tell me whats wrong and how much it will cost.

4. When the repair was finished, and Don went to pick up his van, he took the

van and did not pay the whole repair bill. Did the repair shop have the right to

hold the van until they got paid?

No they didnt have the right because it costed alot and don didnt have that much to pay at one time so don had the right to pay the money in parts.

5. If Don took the repair shop to court, what would you have ruled if you were

the judge? Should the repair shop pay for a replacement rental vehicle?

Should Don pay the whole repair bill? Should the repair shop pay Don for lost

business because he could not pick up and deliver clothes to his customers?

If i were the judge i would not find the repair shop guilty because they had to wait until don came back, because don didnt know the cost. The repair shop should pay for the replacement rental vehicle.

6. What New Zealand laws relate to this story? What do New Zealand laws

say should have been done in this case?

The Consumer Guarantees Act 1993 (CGA) provides that goods and services must meet certain guarantees. In most cases, the manufacturer or the trader is bound by these guarantees.

The Act covers goods you buy, like materials and appliances for the house, as well as the services provided by your architect, designer, builder or other contractors. The Act does not apply to goods bought at auction or tender or at a private sale, for example, if you buy a second-hand mantelpiece through the paper. Neither does it apply when you buy an existing house and the land that goes with it

Monday, 26 November 2012

Costomer bad exprince

TTEC4849 Business Practice and Vehicle Safety

Customer Story of a Bad Experience

Instructions:

Divide up into small groups. Read the following story, and

discuss the following questions in your small groups. Then write your answers

in the space provided.

This is a true story.

The year was about 1958, in California, before there were strong consumer

laws. Don Higgins owned a laundry and dry cleaning business, in which he

used one of the new Volkswagen bus trade vans for his deliveries. He would

pick up dirty clothes from businesses (like restaurants and auto repair shops),

clean them and deliver them back. He liked his Volkswagen van: it had lots of

space to hang the clothes and it got good fuel economy. Up until recently, it

had been very reliable. But lately the engine wasn’t running very well. The

engine was regularly missing and had low power.

So in the morning, Don took his van to his local auto repair shop. He told them

it needed fixing, maybe just a tune up, and he got a ride back to his cleaning

business. Then in mid-afternoon, he went back to pick up his van.

To his surprise, the van wasn’t ready. If fact, the repair shop owner showed

Don the engine that was now out of the van. The exhaust valve for number 3

cylinder was burnt, causing the poor running engine and lack of power. The

shop owner said he could have the engine fixed and back in the van in 3 or 4

days. And the bill would be about $400.00. (In 1958, this was a lot of money.

Don’s monthly mortgage on his house was only about $120.00 per month.)

Don was very upset. He was so upset that I (Steve McAfee) heard about this

as the little boy who lived next door to Don.

Discussion Questions:

1. From Don’s point of view, what was wrong here? What did the shop do

wrong that upset Don so much. (After all, they were fixing his van.)

Don was so upset becasue they didnt fix the car in the time they had , they waited until don came the following afternoon and they told him then, they said it would take 3-4 days to fix it, don worked with his car to deliver his goods but he cannot do this because his car will be in repair for 3-4 days he can not work.

2. From the repair shop owner’s point of view, what was wrong with Don

getting upset at them? What did they do right or wrong?

The repair shop owner thought that he fixes his car he will tell Don how much it will cost

3. What should have been done in this circumstance? If you were Don, what

would you have wanted to be done?

I would want the repair owner to wait until i coem to tell me whats wrong and how much it will cost.

4. When the repair was finished, and Don went to pick up his van, he took the

van and did not pay the whole repair bill. Did the repair shop have the right to

hold the van until they got paid?

No they didnt have the right because it costed alot and don didnt have that much to pay at one time so don had the right to pay the money in parts.

5. If Don took the repair shop to court, what would you have ruled if you were

the judge? Should the repair shop pay for a replacement rental vehicle?

Should Don pay the whole repair bill? Should the repair shop pay Don for lost

business because he could not pick up and deliver clothes to his customers?

If i were the judge i would not find the repair shop guilty because they had to wait until don came back, because don didnt know the cost. The repair shop should pay for the replacement rental vehicle.

6. What New Zealand laws relate to this story? What do New Zealand laws

say should have been done in this case?

The Consumer Guarantees Act 1993 (CGA) provides that goods and services must meet certain guarantees. In most cases, the manufacturer or the trader is bound by these guarantees.

The Act covers goods you buy, like materials and appliances for the house, as well as the services provided by your architect, designer, builder or other contractors. The Act does not apply to goods bought at auction or tender or at a private sale, for example, if you buy a second-hand mantelpiece through the paper. Neither does it apply when you buy an existing house and the land that goes with it

Costomer bad exprince

TTEC4849 Business Practice and Vehicle Safety

Customer Story of a Bad Experience

Instructions:

Divide up into small groups. Read the following story, and

discuss the following questions in your small groups. Then write your answers

in the space provided.

This is a true story.

The year was about 1958, in California, before there were strong consumer

laws. Don Higgins owned a laundry and dry cleaning business, in which he

used one of the new Volkswagen bus trade vans for his deliveries. He would

pick up dirty clothes from businesses (like restaurants and auto repair shops),

clean them and deliver them back. He liked his Volkswagen van: it had lots of

space to hang the clothes and it got good fuel economy. Up until recently, it

had been very reliable. But lately the engine wasn’t running very well. The

engine was regularly missing and had low power.

So in the morning, Don took his van to his local auto repair shop. He told them

it needed fixing, maybe just a tune up, and he got a ride back to his cleaning

business. Then in mid-afternoon, he went back to pick up his van.

To his surprise, the van wasn’t ready. If fact, the repair shop owner showed

Don the engine that was now out of the van. The exhaust valve for number 3

cylinder was burnt, causing the poor running engine and lack of power. The

shop owner said he could have the engine fixed and back in the van in 3 or 4

days. And the bill would be about $400.00. (In 1958, this was a lot of money.

Don’s monthly mortgage on his house was only about $120.00 per month.)

Don was very upset. He was so upset that I (Steve McAfee) heard about this

as the little boy who lived next door to Don.

Discussion Questions:

1. From Don’s point of view, what was wrong here? What did the shop do

wrong that upset Don so much. (After all, they were fixing his van.)

Don was so upset becasue they didnt fix the car in the time they had , they waited until don came the following afternoon and they told him then, they said it would take 3-4 days to fix it, don worked with his car to deliver his goods but he cannot do this because his car will be in repair for 3-4 days he can not work.

2. From the repair shop owner’s point of view, what was wrong with Don

getting upset at them? What did they do right or wrong?

The repair shop owner thought that he fixes his car he will tell Don how much it will cost

3. What should have been done in this circumstance? If you were Don, what

would you have wanted to be done?

I would want the repair owner to wait until i coem to tell me whats wrong and how much it will cost.

4. When the repair was finished, and Don went to pick up his van, he took the

van and did not pay the whole repair bill. Did the repair shop have the right to

hold the van until they got paid?

No they didnt have the right because it costed alot and don didnt have that much to pay at one time so don had the right to pay the money in parts.

5. If Don took the repair shop to court, what would you have ruled if you were

the judge? Should the repair shop pay for a replacement rental vehicle?

Should Don pay the whole repair bill? Should the repair shop pay Don for lost

business because he could not pick up and deliver clothes to his customers?

If i were the judge i would not find the repair shop guilty because they had to wait until don came back, because don didnt know the cost. The repair shop should pay for the replacement rental vehicle.

 

6. What New Zealand laws relate to this story? What do New Zealand laws

say should have been done in this case?

The Consumer Guarantees Act 1993 (CGA) provides that goods and services must meet certain guarantees. In most cases, the manufacturer or the trader is bound by these guarantees.

The Act covers goods you buy, like materials and appliances for the house, as well as the services provided by your architect, designer, builder or other contractors. The Act does not apply to goods bought at auction or tender or at a private sale, for example, if you buy a second-hand mantelpiece through the paper. Neither does it apply when you buy an existing house and the land that goes with it

TTEC 4848 Engine management system

ayob4848 Engine manegment
10/11/12

TTEC 4848 Engine management system

Engine control unit

4848 ayob aghazi

AYOB AGHAZI 4848
15/11/12

Anti-Lock Brake System (ABS) & CAN

ANTI-LOCK BREAKING SYSTEM (ABS)

Theory:

Anti-lock Braking system (ABS) is a very important feature in modern vehicles. During sudden braking it allows for better control, steer-ability, and stability while stopping vehicle in the shortest distance and time. (Note ABS only kicks in when brakes are fully applied)

Types of ABS: There are 3 types

• 1 Channel
• 3 Channel
• 4 Channel

There are two main types of wheel sensors on modern vehicles and they are

1. Magnetic inductive pick up type (Analogue signal)
2. Hall Effect which sends an On/Off digital signal

On the graph below is an example of a hall effect type sensor that switches 5V every 2 seconds.

Below is an example of an analogue signal with a frequency of 0.5Hz and a maximum of 3volts

­Stopping a car in a hurry on a slippery road can be very challenging. Anti-lock braking systems (ABS) take a lot of the challenge out of this sometimes nerve-wracking event. In fact, on slippery surfaces, even professional drivers can't stop as quickly without ABS as an average driver can with ABS.
In this article, the last in a six-part series on brakes, we'll learn all about anti-lock braking systems -- why you need them, what's in them, how they work, some of the common types and some associated problems

Anti-lock brake pump and

The ABS System

The theory behind anti-lock brakes is simple. A skidding wheel (where the tire contact patch is sliding relative to the road) has less traction than a non-skidding wheel. If you have been stuck on ice, you know that if your wheels are spinning you have no traction. This is because the contact patch is sliding relative to the ic. By keeping the wheels from skidding while you slow down, anti-lock brakes benefit you in two ways: You'll stop faster, and you'll be able to steer while you stop.
There are four main components to an ABS system:

• Speed sensors
• Pump
• Valves
• Controller

­Speed Sensors

The anti-lock braking system needs some way of knowing when a wheel is about to lock up. The speed sensors, which are located at each wheel, or in some cases in the differential. provide this information.

Valves

There is a valve in the brake line of each brake controlled by the ABS. On some systems, the valve has three positions:

• In position one, the valve is open; pressure from the master cylinder is passed right through to the brake.
• In position two, the valve blocks the line, isolating that brake from the master cylinder. This prevents the pressure from rising further should the driver push the brake pedal harder.
• In position three, the valve releases some of the pressure from the brake.

Pump

Since the valve is able to release pressure from the brakes, there has to be some way to put that pressure back. That is what the pump does; when a valve reduces the pressure in a line, the pump is there to get the pressure back up.

Controller

The controller is a computer in the car. It watches the speed sensors and controls the valves.

ABS at Work

There are many different variations and control algorithms for ABS systems. We will discuss how one of the simpler systems works.
The controller monitors the speed sensors at all times. It is looking for decelerations in the wheel that are out of the ordinary. Right before a wheel locks up, it will experience a rapid deceleration. If left unchecked, the wheel would stop much more quickly than any car could. It might take a car five seconds to stop from 60 mph (96.6 kph) under ideal conditions, but a wheel that locks up could stop spinning in less than a second.
The ABS controller knows that such a rapid deceleration is impossible, so it reduces the pressure to that brake until it sees an acceleration, then it increases the pressure until it sees the deceleration again. It can do this very quickly, before the tire can actually significantly change speed. The result is that the tire slows down at the same rate as the car, with the brakes keeping the tires very near the point at which they will start to lock up. This gives the system maximum braking power.
When the ABS system is in operation you will feel a pulsing in the brake pedal; this comes from the rapid opening and closing of the valves. Some ABS systems can cycle up to 15 times per second.

Anti-Lock Brake Types

­Anti-lock braking systems use different schemes depending on the type of brakes in use. We will refer to them by the number of channels -- that is, how many valves that are individually controlled -- and the number of speed sensors.

­Four-channel, four-sensor ABS

This is the best scheme. There is a speed sensor on all four wheels and a separate valve for all four wheels. With this setup, the controller monitors each wheel individually to make sure it is achieving maximum braking force.

Three-channel, three-sensor ABS

This scheme, commonly found on pickup trucks with four-wheel ABS, has a speed sensor and a valve for each of the front wheels, with one valve and one sensor for both rear wheels. The speed sensor for the rear wheels is located in the rear axle.
This sys­tem provides individual control of the front wheels, so they can both achieve maximum braking force. The rear wheels, however, are monitored together; they both have to start to lock up before the ABS will activate on the rear. With this system, it is possible that one of the rear wheels will lock during a stop, reducing brake effectiveness.

One-channel, one-sensor ABS

This system is commonly found on pickup trucks with rear-wheel ABS. It has one valve, which controls both rear wheels, and one speed sensor, located in the rear axle.
This system operates the same as the rear end of a three-channel system. The rear wheels are monitored together and they both have to start to lock up before the ABS kicks in. In this system it is also possible that one of the rear wheels will lock, reducing brake effectiveness.
This system is easy to identify. Usually there will be one brake line going through a T-fitting to both rear wheels. You can locate the speed sensor by looking for an electrical connection near the differential on the rear-axle housing.

DO I pump the brake pedal when stopping in slippery conditions?

You absolutely should not pump the brake pedal in a car with ABS. Pumping the brakes ­is a technique that is sometimes used in slippery conditions to allow the wheels to unlock so that the vehicle stays somewhat straight during a stop. In a car with ABS the wheels should never lock in the first place, so pumping the brakes will just make you take longer to stop.
In an emergency stop in a car with ABS, you should apply the brake pedal firmly and hold it while the ABS does all the work. You will feel a pulsing in the pedal that may be quite violent, but this is normal so don't let off the brake.

­Anti-lock brake components

Anti-Lock Brake Diagram

Now let's put the parts together to see how anti-lock brakes work as a whole. This diagram provides both a closeup view and an example of where the brakes are located in your vehicle.
­For more information on anti-lock brakes and related topics, check out the links on the next page

Is anti-lock brakes really work?

Anti-lock brakes really do help you stop better. They prevent wheels from locking up and provide the shortest stopping distance on slippery surfaces. But do they really prevent accidents? This is the true measure of the effectiveness of ABS systems.
The Insurance compony for in united state(IIHS) has conducted several studies trying to determine if cars equipped with ABS are ­involved in more or fewer fatal accidents. It turns out that in a 1996 study, vehicles equipped with ABS were overall no less likely to be involved in fatal accidents than vehicles without. The study actually stated that although cars with ABS were less likely to be involved in accidents fatal to the occupants of other cars, they are more likely to be involved in accidents fatal to the occupants of the ABS car, especially single-vehicle accidents.
There is much speculation about the reason for this. Some people think that drivers of ABS-equipped cars use the ABS incorrectly, either by pumping the brakes or by releasing the brakes when they feel the system pulsing. Some people think that since ABS allows you to steer during a panic stop, more people run off the road and crash.
Some more recent information may indicate that the accident rate for ABS cars is improving, but there is still no evidence to show that ABS improves overall safety this is one type sensor.

 

 

 

 

Anti-Lock Brake Types

­Anti-lock braking systems use different schemes depending on the type of brakes in use. We will refer to them by the number of channels -- that is, how many valves that are individually controlled -- and the number of speed sensors.

­Four-channel, four-sensor ABS

This is the best scheme. There is a speed sensor on all four wheels and a separate valve for all four wheels. With this setup, the controller monitors each wheel individually to make sure it is achieving maximum braking force.

Three-channel, three-sensor ABS

This scheme, commonly found on pickup trucks with four-wheel ABS, has a speed sensor and a valve for each of the front wheels, with one valve and one sensor for both rear wheels. The speed sensor for the rear wheels is located in the rear axle.
This sys­tem provides individual control of the front wheels, so they can both achieve maximum braking force. The rear wheels, however, are monitored together; they both have to start to lock up before the ABS will activate on the rear. With this system, it is possible that one of the rear wheels will lock during a stop, reducing brake effectiveness.

One-channel, one-sensor ABS

This system is commonly found on pickup trucks with rear-wheel ABS. It has one valve, which controls both rear wheels, and one speed sensor, located in the rear axle.
This system operates the same as the rear end of a three-channel system. The rear wheels are monitored together and they both have to start to lock up before the ABS kicks in. In this system it is also possible that one of the rear wheels will lock, reducing brake effectiveness.
This system is easy to identify. Usually there will be one brake line going through a T-fitting to both rear wheels. You can locate the speed sensor by looking for an electrical connection near the differential on the rear-axle housing.

Should I pump the brake pedal when stopping in slippery conditions?

You absolutely should not pump the brake pedal in a car with ABS. Pumping the brakes ­is a technique that is sometimes used in slippery conditions to allow the wheels to unlock so that the vehicle stays somewhat straight during a stop. In a car with ABS the wheels should never lock in the first place, so pumping the brakes will just make you take longer to stop.
In an emergency stop in a car with ABS, you should apply the brake pedal firmly and hold it while the ABS does all the work. You will feel a pulsing in the pedal that may be quite violent, but this is normal so don't let off the brake.

Do anti-lock brakes really work?

Anti-lock brakes really do help you stop better. They prevent wheels from locking up and provide the shortest stopping distance on slippery surfaces. But do they really prevent accidents? This is the true measure of the effectiveness of ABS systems.
The Insurance Institute for Highway Safety (IIHS) has conducted several studies trying to determine if cars equipped with ABS are ­involved in more or fewer fatal accidents. It turns out that in a 1996 study, vehicles equipped with ABS were overall no less likely to be involved in fatal accidents than vehicles without. The study actually stated that although cars with ABS were less likely to be involved in accidents fatal to the occupants of other cars, they are more likely to be involved in accidents fatal to the occupants of the ABS car, especially single-vehicle accidents.
There is much speculation about the reason for this. Some people think that drivers of ABS-equipped cars use the ABS incorrectly, either by pumping the brakes or by releasing the brakes when they feel the system pulsing. Some people think that since ABS allows you to steer during a panic stop, more people run off the road and crash.
Some more recent information may indicate that the accident rate for ABS cars is improving, but there is still no evidence to show that ABS improves overall safety
Reference-
google
ayob aghazi

controlled area net work can systems  The CAN Bus is an automotive bus developed by Robert Bosch, which has quickly gained acceptance into the automotive and aerospace industries. CAN is a serial bus protocol to connect individual systems and sensors as an alternative to conventional multi-wire looms. It allows automotive components to communicate on a single or dual-wire networked data bus up to 1Mbps.

Before CAN Bus Since the early 1940's, automakers have continually improved their vehicles' technology by integrating an increasing amount of electronic components. As technology progressed, the vehicles became more complex as electronic components replaced mechanical systems and provided additional comforts, convenience, and safety features. Up until the release of CAN Bus, vehicles contained enormous amounts of wiring which was necessary to interconnect all of the various electronic components. Due to the vast amount of wiring, an after market installation requires the installer not only to understand how the integrated systems communicate with each other, but also requires numerous connections to be made throughout the vehicle. To make matters worse, the vehicle wiring differs between vehicle years, makes, and even models. As a result, installers need to be highly knowledgeable and perform intensive labor for the most trivial after market equipment or the installation shop experiences countless hours of lost time on troubleshooting and sometimes even expensive claims for damaged OEM equipment. During this progression, installation shops have had an increasingly difficult time finding qualified staff that are able to perform everyday installations and as a result, have either had to increase their prices to compensate for the required specialization and labor, or simply had to turn away the customers who owned complex vehicles. Introducing CAN Bus The BMW 850 coupe was the first CAN Bus vehicle to enter the market in 1986. By reducing the vehicles wiring by 2km, the vehicles overall weight was significantly reduced by at least 50kg and using only half the connectors. For the first time, each of the vehicles systems and sensors were able to communicate at very high speeds (25kbps - 1Mbps) on a single or dual-wire communication line as opposed to the previous multi-wire looms. However, the introduction of CAN Bus also increased the vehicles complexity and made after market installations even more difficult and in many cases impossible to perform. In 2006, over 70% of all automobiles sold in North America will utilize CAN Bus technology. Beginning in 2008, the Society of Automotive Engineers (SAE) requires 100% of the vehicles sold in the USA to use the CAN Bus communication protocol while the European Union has similar laws. Several new after market devices have been introduced into the market that utilize the CAN Bus protocol but until now, there have been no new devices that assist the aging after market remote starter and alarm system technology. Now there is an after market module that offers remote starter and alarm connectivity to the CAN Bus communication protocol. The CAN SL is the first after market CAN Bus bypass kit to offer connectivity of aging remote starters and alarms to the new high speed CAN Bus communication protocol.   Modern vehicles are equiped with communication network system whereby various modules communicate with each other by way data bus system to monitor and control vehivle functions. All the communications is done in real time. CAN systen is a more efficient and less expensive (less wires) and has cut down the number of wiring looms used in modern vehicles. Waveform showing CAN High & CAN Low signal The two wave forms are mirror images of each other and their base voltages are 2.1V for CAN Low and CAN High 2.6V CAN High Yellow colour Can Low Blue colour CAN High speed (high priority) actuates such things as: ABS TPS ECT Brake switch light Traction control CAN Low speed (low priority) actuates things such as: Wiper motor Alarm Central locking power windows De-fog switch refrence. google and me

Anti-Lock Brake System (ABS) & CAN

AYOB AGHAZI TTEC 4848 

11 /11/12

Anti-Lock Brake System (ABS) & CAN

ANTI-LOCK BREAKING SYSTEM (ABS)

 

Theory:

Anti-lock Braking system (ABS) is a very important feature in modern vehicles. During sudden braking it allows for better control, steer-ability, and stability while stopping vehicle in the shortest distance and time. (Note ABS only kicks in when brakes are fully applied)

Types of ABS: There are 3 types

• 1 Channel
• 3 Channel
• 4 Channel

There are two main types of wheel sensors on modern vehicles and they are

1. Magnetic inductive pick up type (Analogue signal)
2. Hall Effect which sends an On/Off digital signal

On the graph below is an example of a hall effect type sensor that switches 5V every 2 seconds.

Below is an example of an analogue signal with a frequency of 0.5Hz and a maximum of 3volts

How ABS brakes work

The ABS system prevents your wheels from locking up when you apply extreme pressure to your brake pedal. This is important because wheels which have become locked are essentially useless. When your wheels are locked, your tires will not rotate which means you’re skidding.
The main components of an Anti-lock Breaking system:
1. Brake Disks
2. Wheel Speed Sensor
3. Toothed Gear
4. Hydraulic Control Unit (Hydraulic Modulator)
5. Master Cylinder
6. Brake Calipers
7. Brake booster

Wiring Diagram and wire colours:
Using the wiring diadram I identified the wheel speed sensors and listed their wire colours.
Front Right: Black and white Front Left: Green and Red
Rear Left: Blue Rear Right: Yellow and Brown

1. The reason for the braided wires is to reduce electro-magnetic interference which could affect the operation of the ABS.

2. Fuses that are used in the ABS circuit are listed below:

• F14 fuse box 50A
• FL main 3,0W
• Gauge 10A
• Dome fuse 20A
• Stop fuse 15A
• ECU IG 15A

3. Identify the grounds for the ABS control unit and ABS motor their wire colours and pin numbers

ABS motor grounds
ABS Motor Pin number is 1A on the ABS actuator, colour is white and black

ABS control unit grounds
ECU control unit Pin 7A on ABS ECU, colour red and black and Pin 20A also ABS ECU, red and blue or Pins 4B, red-black and 1A, red-blue and are both on the ABS relays.

4. On the wiring diagram for the ABS actuator, identify which solenoids control which cylinder and note wire colours and pin numbers.

Front Right Wheel:
Pin numbers: 2B and 6B Wire Colours: Red/White and Red/Green respectively

Front Left Wheel:
Pin numbers: 3B and 7B, Wire Colours: Blue/Red and Blue/White respectively

Rear Left Wheel: 1B and 5B, Wire Colours: Bronw/White and Brown/Red respectively
Rear Right Wheel: 4B and 8B, Wire Colours: Green/Black and Green/Yellow respectively

5. Using the diagram below provided as a guide we have identified the correct condition of the inlet and outlet solenoid valves

• When the ABS is operating under normal braking the inlet valve is open and outlet valve is closed
• When the ABS is operating to reduce wheel brake pressure the inlet valve is closed and outlet valve is open
• When the ABS is operating to hold pressure the inlet valve is closed and outlet valve is closed
• When the ABS is operating to increase wheel brake pressure the inlet valve is open and outlet valve is closed

In the 4 senarios described above the ABS motor will be working only be working when
- The the inlet valve is open and outlet valve is closed (ABS is operating to increase wheel brake) pressure.
- The inlet valve is closed and outlet valve is open (ABS is operating to reduce wheel brake pressure)


Graph of a digital signal wheel speed sensor that switches 5 Volts every 2 seconds

Below is a graph of a wheel speed sensor (Analogue signal) of 0.5 Hz and a maximum of +3V showing volts on the vertical axis and time on the horizontal axis.

ABS Demonstrators:
The wheel speed sensor pin out connections to the ECU on the wiring diagram and the demonstrator are listed below:
Left front: ECU Pin# 4 and 5 Right front ECU Pin# 11 and 21
Left rear ECU Pin # 7 and 9 Right rear ECU Pin# 24 and 26

ABS Relays:
K39: 4 pin relay (the relays or switch that powers up the ABS ECU)
K100: 4 pin relay (the relays or switch that powers up the ABS pump)
K38: 5 pin relay (the relays or switch that powers up the ABS HCU)

• ECU pin# for the wire that brings in the power to the ECU: pin 1 (black/red)
• ECU pin# for the wire that controls the relay for the ABS ECU: 15 (Ignition switch/Ignition On)
• The pin for the wire that brings in the power to the ABS pump: 13 (from actuator)
• The pin # for the wire that controls the relay for the ABS pump: 28 (from ECU)

Inductive low speed wheel speed sensor

Inductive high speed wheel speed sensor (frequency and magnitude increased compared to low speed one above)

Wave form of a speed sensor captured on a oscilloscope (AC voltage)

With the wheep speen sensor spinning we measured in AC voltage with a multimter the volatge readings of each sensor:

Left front: 3.2V Right front: 2.79V

Left Rear: 4.09V Right Rear: 2.87V

The volatage differences can be due to differnt gap size, dirt build up on sensor causing to read incorrect;

Magnetic Wheel Speed Sensor showing the toothed gear

Pic. showing two channl pattern of sensor waveform being actuated by the relay and switching on of the power to the ABS pump

Speed Sensor Gap:
Front right: 0.406 mm
Front left: 0.66 mm
Rear right: 0.406 mm
Rear left: 0.558 mm
All the gap fall within specifications. normal gap should be within 1mm

Reflection:

ABS or Anti-lock Breaking Sysytem allows for better breaking (shorter breaking distance) while still maintaining control and steerability.

The ABS signal coming from the wheel speed sensor is a sine waveform and when wheel speed the signal's frequency and magnitude increases and decreases when speed is reduced.

There are certain things that can go wrong with it. when ECU the detetects a problem it triggers or illuminates the engine check light to indicate fault.

Many things can affect signal and trigger check light like if work is done on wheel bearing, dirt covers wheel speed sensor, broken gear tooth etc. In things like this the code has to be cleared to turn check light off.

Controlled Are Network (CAN) SYSTEMS

Modern vehicles are equiped with communication network system whereby various modules communicate with each other by way data bus system to monitor and control vehivle functions. All the communications is done in real time.

CAN systen is a more efficient and less expensive (less wires) and has cut down the number of wiring looms used in modern vehicles.

Waveform showing CAN High & CAN Low signal

The two wave forms are mirror images of each other and their base voltages are 2.1V for CAN Low and CAN High 2.6V

CAN High Yellow colour

Can Low Blue colour

CAN High speed (high priority) actuates such things as:

• ABS
• TPS
• ECT
• Brake switch light
• Traction control

CAN Low speed (low priority) actuates things such as:

• Wiper motor
• Alarm
• Central locking
• power windows
• De-fog switch

refrence.
google and me

OPERATIONAL AMPLIFIERS ("OP-AMP") & MOSFETS

Vehicle Electrical and Electronics 4847 

Oxygen Sensor unit

Theory and operation

The oxygen sensor is located in the exhaust system and it detects the amount of oxygen in the exhaust by sending a voltage signal which ranges between 0.2V and 1.2V. This data to the ECU which then determines the amount of fuel required to keep the engine running at its optimum level depending on factors such as load, speed, etc. Note for the oxygen sensor to starts to work when the engine reaches operating temperature.

A oxygen sensor produces a voltage normal oxygen sensor signal voltage ranges between 0.2V and 1.2V. When more air less fuel (lean condition) is sensed by oxygen sensor outputs a 0.2V~0.4V and when a near perfect Air/Fuel ratio (stiochiometric range) it outputs 0.5V~0.65V and when more fuel than air (rich condition) is sensed the output voltage by the oxygen sensor is about 0.65V~1.2V

List of Components used for this project:

• 1x Op-Amp, Max supply voltage ±16 or 32V
• 1x 10kΩ, 3x480 kΩ, 1x 270Ω, 1x 470Ω, 1x 270Ω Resistors
• 3x LED (1x Green, Red and Orange)
• 2x Diodes (1N4001), Max Pd = 2.5W, Max I = 1A @ 75ºC, Max reverse voltage = 100V
• 1x Zener Diode (9V1), this a 9.1V capacity Zener diode 2x Capacitors (0.1uF), the capacitors are used to smoothen out the current in the circuit.

Source upply voltage(Vs) = 12V
LED = 1.8V
IzRm = 5.6mA (This current value was abtained from the data sheet)

We have 12v coming in from the source and as it passes D2 diode there is a voltage drop of 0.6V. So we have 11.4V going to R5. The supply voltage is further used up by R5 and the voltage drop across R5 is (11.4-9.1)=2.3V
Using Ohms Law
V = I*R
R = V/I
R5= 2.3/0.0056 = 410.7 Ohms

Now we know R6 = 10K, so we can find current along R6
the voltage drop across R6 is (9.1V-0.63V) = 8.47V
therefore current across R6 is: I = V/R = 8.47/10000 = 0.000847A (0.847mA)

Since it is a series circuit the same current flows through R6, R7,and R8
R8 = V/I = (0.63-0.23)/0.000847 = 472 Ohms.
similarly R7 = 0.23/0.000847 = 271.5 Ohms
To find R1, R2, R3, and R4 we were given current across this part of the circuit (9.5mA)
Voltage drop across R2 is 12-0.6-1.8 = 9.6V
V = I*R
R2 = 9.6/0.0095 = 1010 Ohms
voltage drop across R3 = 12-0.6-0.6-1.8 = 9V
R3 = 9/0.0095 = 947 Ohms
voltage drop across R4 = 12-0.6-1.8 = 9.6V
R4 = 9.6/0.0095 = 1010 Ohms.

 Explnaton how the  circut work.                                                                            
1. GREEN LED on  This happens when pin 13 of the opamp is getting 0.23V and pin 12 wich is conected to sensor input is getting less than 0.23V from the sensor input this allwos the out put at pin 14 ground the circut wich turns the green light on when the sensor input gose above 0.23 available voltag at pin 12 exceds that of pin13 the green LED is turn off.  
2.Yellow LED       

Pin 10 is getting 0.23V but when available voltages at pin 9 and pin 3 are greater than 0.23V and at the same time pin 2 is getting 0.63V. What happens is that available voltage at pin 9 is greater than pin 10 and at the same time pin 2 is greater than pin 3 and so there is virtually no power flowing through D3 diode hence, power coming from the supply or source (9.6V) is grounded at pin 11 by the circuit and the yellow LED turns on. But when when input at pin 9 drops below 0.23V the yellow LED is turned off and the green LED turns on instead.

3.RED LED This happens when input at pin 6 is greater than 0.63V, and since pin 5 is connected to constantly to 0.63V. During this time power at source flows through and the circuit is grounded and the red LED is turned on. When sensor input (pin 6) is less than 0.63V then the red LED is turned off

OPERATIONAL AMPLIFIERS ("OP-AMP") & MOSFETS

OPERATIONAL AMPLIFIERS ("OP-AMP") & MOSFETS

What is Operational Amplifier "OP-Amp"?
Operational Amplifiers are electronic circuits. They are ideal linear devices and thus are used for signal amplification, filtering. They awere initially used for mathematical comutations like addition, subtraction, etc.

Fig. 1. Symbol of an Op-Amp

An Op-Amp has two inputs and an output (Vout) which are connected voltage rail (+Vss & -Vss)
+ input is called "Non inverting input"
- input is called "Inverting input"

How Op-Amps works?
Op-Amps are current controlled. Op-Apms work in many different ways. They can be used as a inverting/non-inverting voltage amplifier.

The output is dependant on the voltage difference between the two inputs. The output takes the value of the greater of the two input values. for example, in the fig 2. below since the greater Vin is 5v, hence the output would be whatever is on the negative (-Vss)

Fig. 2.

What is a Mosfet?
Metal Oxide Semiconductor Field Effect Transistor is one type of a semiconductor and it is mainly used in electronics as a switching device. MOSFETS's have three terminals Gate (G), Source (S), and Drain (D). There are two types of Mosfets N-channel and P-channel

Fig 3 Mosfet

G (Gate), D (Drain), S (Source). P-Chanel are doped with holes and the N-Chanel are doped with electrons.

Types of Mosfets:

1. Depeletio type
2. Enhancement
   
   
   

Characteristics of Mosfets:



• Mosfets are voltage controlled i.e. O2 sensor
• Mosfets have positive temperature co-efficient (conduct less current as its temperature increases)
• Mosfets must be handled with care to protect against damage by static elctrictricity.
• Mosfets can get very hot so again handle with care

Mosfets are voltage controlled and based on conventional current flow theory (from positve to negative).

References:

1. http://forums.overclockers.com.au/showthread.php?t=962539
2. http://www.knowledgerush.com/kr/encyclopedia/Transistor/
3. http://www.societyofrobots.com/electronics_advanced_components_tutorial.shtml

VEHICAL ELECTRONIC AYOB AGHAZI 4847

Identifying, Testing and Troubleshooting Semicondutor Components

Identifying, Testing and Troubleshooting Resistors:

Experiment No.1: Resistors
Resistors are used to control flow of current. From Ohm's law we can see that the resistance is inversely proportional to the current flow; that is as the resistance increases the current decreases.

Resistors are very important and widely used in electrical and electronic components.
Resistors are colour coded for identification purposes. There are four main colour bands.

• First two or three bands are the numbers to be written down
• Next band is the multiplier (how many zeros to add the number)
• Gold multiplier makes one decimal place smaller, silver makes two decimal places smaller
• Last band to the right is tolerance values

Colour Codes for Resistors

Obtain 6 different resistors of different values and determine their value in two different ways:

• Use the coulr code to calculate the value of the resistor
• Include the maximum and minimum tolerance value of each resistor
• Then measure the resistor value with a multimeter.

 

 

 

 

 

 

 

Value (colour codes)	Measured value (multimeter)
Yellow (4), violet (7), black (0), black (0), gold (5%)	467Ω

Resistor Color Code Calculator Color Band 1 Color Band 2 Color Band 3 Results OR Resistor Color Code Chart Band Color Options Band #1 Possible Band #2 Possible Band #3 Possible Multiplier Value For Band 3 Band #4 Value Tolerance Black 0 1 1 Brown 1 1 1 10 Red 2 2 2 100 Orange 3 3 3 1,000 Yellow 4 4 4 10,000 Green 5 5 5 100,000 Blue 6 6 6 1,000,000 Violet 7 7 10,000,000 Gray 8 8 100,000,000 White 9 9 1,000,000,000 None 20% Silver 10% Gold 5% Resistor Color Code Information The resistor color code is a long standing standard in both the electronics and electrical industries, indicating the value of resistance of a resistor. Resistance is measured in ohms and there is a foundation for it called Ohm's Law. (Want to know about Ohm's Law? If so, please click here or click here!) Each color band represents a number and the order of the color band will represent a number value. The first 2 color bands indicate a number. The 3rd color band indicates the multiplier or in other words the number of zeros. The fourth band indicates the tolerance of the resistor +/- 20%, 10% or 5%. In most cases, there are 4 color bands. However, certain precision resistors have 5 bands or have the values written on them, refining the tolerance value even more. There is no standard (TANS) however, for the 5th band. From one manufacturing company to another, the 5th band may indicate 2%, 1%, 1/2% or even closer, according to their own standards. Color bands are usually found on resistors that have a wattage value of 1/8 to 2 watts; though it is rare, there are some 5 watt resistors that are banded. There are also some capacitors that are color coded. See our Capacitor Color Code Calculator.

 

Brown (1), black (0), red (2)	0.98kΩ
Green (5), blue (6), red (2), gold (5%) 5600±5% or 280= min5320Ω and max 5880Ω	5.54kΩ
Orange(3), orange(3), brown(1), gold(5%)	327Ω
Brown (1), black (0), brown (1), gold (5%)	98.3Ω
Brown (1), black (0), orange (3), gold (5%)	99.6kΩ

Choose two resistors and record their indivitual Ohm resistance values and measured with a multimeter

Resistor 1: 468Ω Resistor 2: 10kΩ

1.1 Resistors in series:

calculated value 1 & 2 in series: Rt = R1+ R2 = 10468Ω

measured value 1 & 2 in series: 10480Ω

1.2 Resistors in parallel:

calculated value 1 & 2 in parallel: Rt= R1*R2/R1+R2 = 447Ω

measured value 1 & 2 in series: 10480Ω

In experiment 1. I measured and and calculated resistor values in two way. first from the colour code and then I measured the resistor value with a multimeter to verify my result from the colour code values. the result of both methods of resistor value calculation was about the same thus proofing both methods to be right.

In addition to calculating resistor values, we also did a small test to check the difference between when resistors are in series and parallel.

We have also prooved that when resistors are connected in series their total resistance is the sum of the indivitual resistors (Rt = R1 + R2 + R3 + .... + Rn ).

Similarly, we have a shown that when resistors are in parallel their total resistance is smaller than the smallest resistor in the circuit and can be calculated by using this formula

(1/Rt = 1/R1 + 1/R2 + 1/R3 + ....+ 1/Rn).

Experiment 2. Diodes


Diodes are electrical device that only allows current flow in one direction (dirction of arrow). positive side is anode and negative is cathode.
A diode can behave as an insulator and a conductor depending on how it connected (formard or reverse). when current flows in the forward direction the voltage drop accross the doide is very small so it does not take much effort to bush through the doide. And in the reverse direction no current flow hence the zero voltage drop recorded.

Exercise: Identifying the anode and cathode of doides using a multimeter.

	Voltage drop in forward biased direction	Voltage drop in reverse biased direction
LED	1.8V	0
DIODE	0.57V	0

Explain how to identify the cathode without a multimeter
Diode: Cathode side of a doide has a band marking.

LED: Short leg of the LED is the cathode.

Calculate the current flowing through diode and compare it against a measured result usung meter.

Calculated : Measured using meter:
known: V=5v, R=1kΏ. (1000 Ώ.) I = 0.005mA
V=I*R
I=V/R= 5/1000 = 0.005A (5mA)

Is the reading as you expected; explain why or why not?

Yes, the reading was as expected. From Ohm's law we learnt that resistance and current are inversely proportional. In this case we were working with a relatively big resistor 1kΏ. And that is the reason for the tiny current flow. On the other hand if we had low resistance our current would have increased proportionally.

Calculate the voltage drop across the diode:

Since we have all ready know the current flowing through the diode to find the voltage drop across diode we use Ohm's law again:

V=5v, I= 0.005A

V = I*R = 0.005 x 5 = 0.66V

Using the table of data above, the maximum value of the current that can flow through ther given diode is 1A.

For R = 1kΏ, the maximum value of Vs so that the diode operates in a safe region is 1000V.

Using same circuit we only replace diode with an LED, calculate the current, then measure and check answer.

Calculated : Measured using meter:
known: V=5v, R=1kΏ. (1000Ώ.) I = 0.003mA
V=I*R
I=V/R= 5/1000 = 0.005A (5mA)

The result shows that there is no change to current flow in the circuit whether we use an LED or a doide. The reason is that it is the high resistance that is restricting the flow of current in the circuit.

Experiment 3:

Zener Diode: Components: 2x resistors, 1x 5V1 400mW Zener diode (Zd)

For R= 100 Ώ, RL= 100 Ώ, Vs= 12V; What is the value of Vz?
Answer: Vz= 4.97V


Vary Vs from 10V to 15V
what is the value of Vz?

when Vs= 10V Vz= 4.72V
Vs= 15V Vz= 5.1V

Zener doide behaves just like any other doide when forward based until a certain reference voltage is exceeded it becomes reverse biased and maitains the 5V reference voltage regardless of how much higher Vs gets above reference voltage of 5V.
The zener voltage stays relatively constant regardless of the Vs. This the characteristics of a zener diode. It acts as a voltage regulator and are used to maitain constant voltage. Experiment 4:

Components: 1x resistor, 1x 5V1 400mW Zener diode, 1xdiode 1N4007

Exercise: Obtain a breadboard, suitable components and build the circuit.

Vs= 10 and 15V, R= 1kΏ

Voltage drops	10 Volts	15 Volts
Volt drop V1:	4.64V	4.82V
Volt drop V2:	0.67V	0.70V
Volt drop V3:	5.31V	5.50V
Volt drop V4:	4.74V	9.50V
Calculated current (A)	I=10/1000= 0.01A	I= 15/1000= 0.015A

After connecting the various components according to the circuit above we have tested the voltage drops across V1, V2, V3, and V4.

When Vs is varied between 10 and 15 volts, the voltage drop at V1 is maintained at about 5V just about the reference voltage of the Zener diode. While the voltage drop across the normal diode remains at about 0.57V. The current flow in the circuit is very small (10-15mA), hence the seires connection of the circuit.

The Zener diode blocks off any voltage below 5V and bleeds off excess voltage that is why voltage drop at V4 is that high in both cases. The diode regulates the amount of current in the circuit and keeps it within the circuit proper operating conditions and protects it from exposure to excessive voltage that may damage the components.

Capacitors:

Capacitors are used as a charge storing devices in electrical circuits. It consists of two metal plates separated by an insulator. The unit standard of a capacitor is Farad (F).

Experiment 5;
Exercise: First calculate how much time it would take to charge up a capacitor. Then connect the circuit as shown above. Measure the time taken by the capacitor to reach the applied voltage on an oscilloscope. Fill in the chart below and draw the observed waveforms in the graphs below.

1uF= 0.000001 F

Circuit Number	Capacitance (uF)	Resistance (kΏ)	Calculated Time (ms)	Observed Time (ms)
1	100	1	500	400
2	100	0.1	50	100
3	100	0.47	235	210
4	330	1	165	1600

Calculation procedure in here I will only show calculation of circuit number 1;

To convert 100uF to Farad (F) multiply 100 by 0.000001 = 0.0001F

T= R*C*5

T= 1000*(100*0.000001)*5= 0.5s (500ms)

Graphs:

Circuit 1: (10V/Div and 500ms/Div)

capacitance 100 uF, Resistance 1kΏ

Circuit 2: (10V/Div and 100ms/Div)

capacitance 100 uF, Resistance 100Ώ

Circuit 3: (10V/Div and 100ms/Div)

Circuit 4: (10V/Div and 1s/Div)

capacitance 330 uF, Resistance 1kΏ

from the result of both the calculated and graph we can see that as the resistance is directly proportional to charge time and also the higher the capacitance the longer the charge time.

Experiment 6

Transistors are semiconductors that are uses a small current to turn on a much lager one. They are used to control current flow in a circuit.

There are two type of transistors NPN and PNP

Meter check of a Transistor:

First put meter on diode test mode

Emitter base junction has slightly higher voltage drop that the collector base junction. From here it is easy to name all three junctions of the transistor.

After naming the three junctions, we go on determine whether a transistor is NPN or PNP. To do this we connect (+) lead of multimeter to base of transistor and connect (-ve) lead of meter to either of the other two junctions if we get a small voltage reading on meter then it is a NPN transistor but if we get OL reading and then we reverse the leads (-ve) on base and (+ve) on either one of the other two and we get a small voltage reading then our transistor is PNP.

Identifying the legs of transistor with a multimeter.

Transistor No.	Vbe	Veb	Vbc	Vcb	Vce	Vec
NPN	0.738V	OL	0.73V	OL	Ol	OL
PNP	0.739V	OL	0.74V	0.735V	OL	OL

Experiment 7:

Transistor as a switch
Components: 1x small signal NPN transistor, 2 resistors.

Exercise: connect the circuit and switch on the power supply.

Connect the multimeter between base and emitter and note voltage reading.
Voltage between base and emitter is measured to be 0.8V. We then connected between collector and base the voltage reading was very small about 0.05V.

This indicates a very small voltage going through Vbe. It is the base that controls the collector. This is sufficient voltage at base and current to flow between collector and base and hence the transistor is on but if there is no enough voltage going through base then that means transistor is off and no flow between Vbe and Vce. The small current flowing through base-emitter is controlling the flow between collector-base flow.

The base-emitter has reached the high enough voltage for current to flow between collector-base (0.05V). since base-emitter acts like a diode. It only creates a connection between collector-base only when the voltage at base-emitter reaches the 0-7V threshold.

Normally a transistor has three regions:

Saturated Region is the region where both emitter and collector are forward biased Vce (Zero). When at the saturated region and sufficient current is available then current at Vbe does not raise current at Vce. Used when a transistor is required as a switching device.

Active Region: this is the region in the middle of the chart and it is where power dissipated is highest. This region is used when amplification of small signals is required.

Cut-Off Region: In this region both emitter and collector are reverse biased. Base current is zero, hence no collector flow. Used when a transistor is required as a switching device.

Power dissipated by transistor at Vce of 3V:

P= Vce*Ic= 0.015x3= 0.045W (45mW)

The Gain is ratio between Ic and Ib. It is the multiplying factor that and the reason why transistor is able to turn a small current to control a much larger current.

β=Ic/Ib

Vce @ 2V: β= Ic/Ib= 20mA/0.8mA= 25

Vce @ 3V: β= Ic/Ib= 15mA/0.5mA= 30

Vce @ 4V: β= Ic/Ib= 7mA/0.2mA= 35

Gain increases with increase in Vce.

Experiment 8

set up the circuit below on a board. Use a 470R for Rc and BC547 NPN transistor.

Vary base resistor and measure changes in voltage and current for Vce and Vbe, Ic and Ib. Then plot a load line.

Result:

Rb 47k	Vbe 0.72V	Vce 0.09V	Ib 0.10mA	Ic 0.14uA
Rb 220k	Vbe 0.70V	Vce 0.60V	Ib 0.8mA	Ic 0.08mA
Rb 270k	Vbe 0.69V	Vce 1.05V	Ib 0.6mA	Ic 0.12mA
Rb 330k	Vbe 0.69V	Vce 1.42V	Ib 0.2mA	Ic 0.12mA
Rb 1M	Vbe 0.85V	Vce 2.58V	Ib 0.08uA	Ic 0.15mA

From the test it evident that Vce increases as Rb is increased but Vbe does not show change and stays about the same. Vce changes as the transistor changes depending on which region the transistor is in. low for saturated and high as it reaches the active region.

Ib is inversely proportional to Ic . Ib reaches its highest when the resistance is at its lowest (47k) and Highest at 1M. Ic is at its maximum when

This is as expected since the more restriction to flow of current the is the lower the current is going to be.