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Engines are complex machines are controlled by a computer called the ECU or Engine Control Unit. This little baby is the brains of the car. But even the ECU is deaf and dumb unless it has the proper input. Sensors provide the input to the ECU.

This article is about these sensors. The ECU is further subdivided into different functions but for this article suffice to say that it makes the decisions based on sensor input.

There's a plethora of sensor suites in a car that track a host of functions. A car's ECU controls "ignition timing, fuel delivery, emission controls, transmission shifting, cruise control, engine torque reduction (if the vehicle has antilock brakes with traction control) and charging output of the alternator."

To be more specific, here are some of the more important sensors for the ECU:

Coolant Sensor. The ECU monitors the temperature of the coolant so it can determine it can switch its mode into a "closed loop feedback fuel control" after startup. After startup, the engine is usually cold and designers left the engine in open loop mode until it the ECU determines it reaches the right operating temperature to switch to closed loop.

During open loop, the engine is not being very efficient and gas is wasted because the mix is too rich uncontrolled. Damaged coolant sensors will also cause this.

Oxygen (O2) Sensor. O2 Sensors are usually located near the exhaust manifold of most cars. There can be about 1 to as much as 4 O2 sensors in cars. The role of the O2 sensor is to measure the amount of unburned oxygen in the exhaust. They do this by comparing the temperature inside the exhaust pipe to that of the outside atmosphere. This sends a signal to the ECU to adjust the air-fuel mix and timing accordingly.

Damaged O2 sensors will also cause the ECU to deliver an air-fuel mix that is too rich for the engine.

Manifold Absolute Pressure (MAP) Sensor. MAP sensors are located near the intake manifold to measure engine load or the intake vacuum.

When vacuum occurs, the engine is usually on idle and the ECU will shift the timing and fuel ratio accordingly. When the car is running, the engine is taking in more air, which signals the ECU to enrich the mixture for more power. Vacuum is still present but is variable when the engine is in operation.

Mass Air Flow (MAF) Sensor. The MAF sensor detects the volume of air entering the engine. It's vital element is usually a heated filament that is put against incoming air in the tube to measure airflow and density. Changes in temperature sends a signal to the ECU to respond to the needs of the engine accordingly.

Throttle Position Sensor (TPS). The TPS monitors the throttle position which accordingly measures the engine's load, acceleration, deceleration, idle or wide open. The ECU utilizes this data to determine the air-fuel ratio adjustments.

Crankshaft Position Sensor (CPS). The CPs is used to determine the position of the crankshaft and number 1 cylinder. This specifically is used to control the timing of ignition and the injection of fuel. This can also measure the RPM (revolutions per minute).

Failure of the CPS will render the car inoperable.

The Effect of 3Rd Party Mods

Manufacturers usually would warn against 3rd party modifications to the engine or electronics. Despite this a large industry has sprung up to take advantage of some shortcomings of standard production vehicles.

One area of 3rd party modification involves improving the air-fuel mixture with other substances. More specifically hydrogen.

Hydrogen is a gaseous substance that is combustible. The benefits of the introduction of hydrogen to internal combustion is that:

-Engines become more quieter, knocking and pinging is reduced
-Emissions give off a cleaner burn
-Hydrogen when burned turns to water vapor out the tailpipe
-Hydrogen raises the octane level of gasoline, encouraging combustion at the piston's top dead center
-Less fuel is used when mixed with hydrogen, giving better fuel economy.
-The engine is cooled which promotes better performance

Things to consider:

Introduction of hydrogen to a regular internal combustion engine will in time influence the ECU to enrich the mixture further. This is due to the O2 sensor detecting more oxygen in the exhaust.

The ECU is programmed from the factory to maintain a "stochiometric" or air-fuel mixture of about 14.7 parts oxygen to 1 part fuel. Even if the engine is performing better at a leaner mixture, it is only capable of following its programming.

The ECU will then pump more fuel into the mixture to meet the 14.7:1 ratio, ruining performance.

There is still hope!

Fortunately, the problem with the ECU can be addressed. The introduction of a controller to the ECU's sensors can nudge the ECU to accept a leaner fuel mix with no need for expensive modifications:

These are by far the most easily modifiable with the least cost between $20 to over $100 USD.

Are these safe?

Hydrogen systems have been tried and tested by dozens of alternate fuel enthusiasts for years and they attest to the safety of both systems.

Several hydrogen generation systems have already been developed to deliver hydrogen-as-needed-only. When the engine is off, the danger of hydrogen sparks is nil because the process to create hydrogen is by electricity in a water medium. No electricity, no hydrogen.

As an alternate fuel enhancement, hydrogen technology has matured and delivers the best value in terms of return on investment over other more expensive enhancement systems.

For more detailed information on increasing engine performance, fuel efficiency without the need for a mechanic or a degree in engineering, please visit the url below.

Erwin Chua MCP, MCDST has been involved with cars since he was 22. He has a still-pending Master of Arts in Philosophy from De La Salle University - Manila after he decided to leave the academe in pursuit of the true Way. Currently, he is based in Penang, Malaysia spending his time working out, tinkering and puttering away on his Toyota, practicing the Way, building web sites, and writing articles on technology, health, nutrition, body conditioning, healing and travel.

For more very useful information on increasing fuel efficiency, mileage, and saving petrol. Visit us at: http://www.savepetrolfast.com

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The cord Blood which was discarded soon after the birth of a baby is regarded as a life saving device for the future generations of a family. It has thereby become imperative to save the precious blood which is rich in stem cells necessary for the treatment of several life threatening diseases. In the past ten years, several cord blood transplantations have been performed worldwide as an alternative for treating cancer and serious genetic disorders. The first cord blood transplant was done in 1988

There are various sources of retreiving stem cells and Umbilical cord blood is one of the three sources for obtaining the blood-forming cells used in transplants. The other two sources are bone marrow and peripheral (circulating) blood. It is collected at the time of delivery after the birth of the baby. The blood from the cord is collected carefully by the hospital staff who are trained in the service. It is then tested, frozen and stored at a cord blood bank for future use. The stored blood is called a cord blood unit (cbu).

The National Marrow Donor Program (NMDP) Registry includes more than 70,000 cbu. Doctors search the NMDP Registry of adult marrow or peripheral blood cell donors and cbus to find a suitable HLA match for their patients who need a transplant. If selected, the matching blood is transfused to a patient. The transplant process is the same as for marrow and peripheral blood cell transplants

The use of cord blood transplants has grown for both children and adults. It is used more often in children because an umbilical cord holds a limited amount of blood. The number of blood-forming cells in a transplant should match the size of the patient - usually younger patients need fewer cells and older patients need more cells. Some cbus may not have enough blood-forming cells for some patients.

Doctors are trying different ways to increase the number of cells in a cbu so they can use cord blood for larger patients. One method being studied is to give a patient two units. Another method being studied is to grow the number of cells in a in a laboratory before giving it to the patient.

When your doctor searches the NMDP Registry, he or she will choose the best cell source for you. That may be marrow or peripheral blood from an adult donor or it may be a cb unit. A doctor might choose cord blood because of some of the ways it differs from marrow or peripheral blood.

A close match between the patient and the donor or cbu can improve a patient's outcome after transplant. Even though a closely matched one is always preferred, clinical studies suggest the match may not have to be as close as is needed for marrow or peripheral blood transplants. It can take two months or more to find an unrelated marrow or peripheral blood donor. A unit can be selected and delivered to the transplant center in less than two weeks. Your doctor may choose cord blood if you need a transplant quickly.

However there are chances that your doctor might not approve of Cord blood transplantation. The possible reasons for this are:

There may not be enough blood-forming cells in a unit for the size of the patient.

It usually takes longer for cord blood cells to engraft (begin to grow and create new blood cells and an immune system). Until the cells engraft, the patient is at a high risk for infection.

Patients cannot get backup cells from the same cbu. If a patient's transplanted marrow or peripheral blood cells do not engraft or the patient relapses, the patient may be able to get a second donation from the same adult donor. After a transplant, this option is not available. However, doctors may be able to use a different unit or a backup adult donor instead.

Cord blood transplants also have all the same risks as marrow and peripheral blood transplants. The risk of infection may be higher after a cord blood transplant because of the longer time to engraft.

If you have questions about whether a cord blood transplant is right for you, talk with your doctor. Every patient's situation is different. Your transplant doctor knows your situation and can help you make choices about your treatment.

cord blood plays a vital role in the treatment of life-threatening blood diseases. In such a case cord blood transplant may be an option.

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