10-07-2010, 07:36 AM
Our gas guzzling automobiles are the main source of air pollution and efforts are underway to reduce emission of polluting gases through the exhaust. There are two main courses of action to reduce air pollution. One is changing the source fuel by opting for electric cars, hydrogen cars and the second approach is to modify existing petroleum fuel based automobile technology to reduce emissions. One such measure is aimed at reducing nitrogen oxide (NOx) emissions and is called the exhaust gas recirculation (EGR) technology. In this article, I explain the utility of an EGR valve, how it works and why is it necessary to reduce emissions.
EGR valves are fitted in gasoline (petrol) and diesel engine assemblies of most cars today. They are an important modification made to car engines, in an effort to make them eco-friendly. Most importantly, EGR valve technology reduces emissions, without compromising the engine efficiency substantially. Before we understand how EGR valves work, one needs to know why there was a necessity to develop such a device in the first place. This is what we discuss in the next section.
Need For EGR Valve
EGR technology was developed to counter the growing threat of mono nitrogen oxide (NOx) production which occurs during combustion in engines. When emitted in the air, these gases (NO and NO2) react with other volatile organic compounds to create photochemical smog which has a harmful effect on the respiratory system. These nitrogen compounds react with moisture in the atmosphere, to produce nitric acid which is a major component of the precipitation that occurs in the form of acid rain. The combustion engines are ideal sites for reaction of nitrogen and oxygen due to the high temperatures that exist inside, reaching and exceeding 1600o Celsius. So, the EGR valve technology was developed to counter this threat of NOx emissions from fuel combustion which contribute substantially to the overall air pollution. The key, to counter it, was to reduce the temperature at which combustion occurs in car engines. Let us see how the EGR valve based technology achieved this objective.
How EGR Valve Works?
As the name suggests 'Exhaust gas recirculation valves', first introduced in 1972, are used to feed back a portion of the exhaust gases emitted by the car engine, back to the combustion chamber. The addition of these volume of gases reduces the quantity of oxygen available for combustion. Also, the addition of exhaust gases made to the air-fuel mixture, increases its specific heat capacity.
Due to both these factors, the adiabatic flame temperature of combustion. That is, the dearth in oxygen and increase in heat capacity, lead to the combustion of a gases at lower temperature. This effectively reduces the amount of mono nitrogen oxide gases created and released. Generally 5% to 15% of the exhaust gases are fed back in spark ignited engines. In diesel engines, the exhaust gases are cooled before they are fed back to the engine.
The efficiency of the engine does get reduced but there is a switching mechanism in place to take care of that. When the engine has a high RPM demand (Wide Open Throttle Conditions) and is in full acceleration mode, the EGR valve action is stopped and exhaust gases are no longer fed back to the engine. This ensures that the engine efficiency is not compromised when the RPM demands are high. It is also turned off when the engine is idling as it can destabilize the engine. Only in the region of mid acceleration, where the engine is between the two extreme conditions of full throttle and idle, does the EGR valve come into play. In modern cars, the action of the EGR valve is controlled by electronic engine controls mechanism.
How to Clean EGR Valve
Controlling emission of polluting gases from a car exhaust was a major challenge for designers of the automobile technology. One of the technological breakthroughs that emerged out of attempts made to control this emission is the EGR (Exhaust Gas Recirculation) mechanism fixed in car engines. In this article, I mainly talk about how to clean EGR valve to ensure its peak performance.
Automotive troubleshooting is a complex task that involves a multitude of small tune up jobs. Dirt, dust, heat and friction are the prime damaging agents of a car's interior mechanism. Car maintenance is all about taking precautions that these destructive agents are kept at bay. That is why knowing small jobs like how to clean EGR valves is essential. Before I share EGR valve cleaning instructions, let us understand the function of an EGR valve and why is it essential that it is cleaned periodically!
About EGR Valves
The concept of 'Exhaust Gas Recirculation' evolved out of the need to restrain the emission of nitrogen oxide compounds from a car's exhaust. Nitrogen oxide compounds are poisonous gases that can cause adverse effects on many biological systems that they come in contact with besides causing smog. Smog reduces visibility. That is why it was important that the emission of these gases be reduced. It is copiously produced in high temperature conditions, inside an engine, in a high concentration mixture of nitrogen and oxygen. Automobile engineers developed the EGR valve mechanism to nip the problem of nitrogen oxide production in the bud.
This was achieved in the following manner using a feedback mechanism. A portion of the exhaust gases are fed back to the engine's combustion chambers. This causes a drop in the temperature of the gasoline-air mixture and reduces the production of nitrogen oxide compounds. The EGR valve's function is to control when and how this feedback is supplied to the engine. The exhaust gases are not fed back when the engine is in high RPM mode or when it is almost idling. This ensures that the car engine's efficiency is not compromised. Thus the EGR valve's functioning is crucial for maintenance of engine efficiency.
EGR Valve Cleaning Instructions
Now that we know the functioning of the EGR valve, let us see why it's important that it is cleaned periodically. The EGR valve can cause a fall in engine efficiency and seriously compromise fuel economy of a car, due to carbon deposition and blocking caused by particulate matter. Clogging can can cause the diaphragm inside the valve to fall into disrepair. That is why it is important that you know how to clean EGR valves and perform the cleaning job once a year. Here are generic instructions on how to clean EGR valves. You will require a wrench set, socket set, scratch awl and phillips screwdriver for the job.
* Disconnect the car battery's negative terminal after which you need to do is to open the car hood and locate the EGR valve. It usually lies on the engine side and has a vacuum hose on top and an electrical connector. Refer to your car manual if you are not able to locate it.
* Remove the vacuum hose and electrical connector.
* Remove the pipe that connects to the EGR valve bottom.
* Then remove the entire EGR valve assembly by unscrewing the nuts holding it to the engine and the gasket, using wrenches. Now you can work on the EGR valve.
* Disconnect the solenoid that is usually attached to at the top of the valve, with a screwdriver.
With the help of a scratch awl, clean the bottom passage of the valve mechanism. This will get rid of the carbon deposits inside. Also clean the pipe attached to it. In case the EGR valve gasket is damaged, replace it. Otherwise just clean it. That's it. You have finished cleaning the EGR valve. Rest of the job is putting it back as it was. To do this, you must retrace your steps and go in reverse, by connecting the solenoid, pipe, vacuum hose, electrical connector and then reattach the EGR valve in its place in the proper reverse order. With that your cleaning job is finished entirely. Reconnect the car battery.
Emission control is a major concern for the automobile industry for a long time now. There have been many innovations in automobile technology, that have helped in bringing down emission and air pollution levels today. One such innovation is the EGR (Exhaust Gas Recirculation) valve technology. This article is aimed at explaining how to replace EGR valve in cars, which is a permanent fixture in most cars today.
What is EGR Valve?
For those who came in late, let me give you some background on exhaust gas recirculation technology, before we go into EGR valve replacement procedure. EGR technology was developed out of the need to reduce nitrogen oxide emissions from automobiles. To achieve this objective, a feedback mechanism was developed that could indirectly reduce nitrogen oxide emissions. This technology reduces nitrogen oxide emission by inhibiting the very process that leads to its creation. The technology works in the following manner. A portion of the exhaust gases emitted from car engine is fed back to combustion cylinder of the car engine.
This exhaust gas feedback displaces the combustive mixture of gases by volume and leads to a drop in the heat of combustion generated in every cycle. Without compromising to a great degree on the pressure generated in the cylinder, the combustion cycle occurs at a lower temperature. Nitrogen oxide compounds are formed faster from a high temperature mixture of oxygen and nitrogen. Since, exhaust gas recirculation valves reduce the combustion temperature in combustion cylinder, comparatively lesser amount of nitrogen oxide is created, which is responsible for creating smog.
EGR valves are fitted in the engine assembly to establish and control this feedback mechanism. The EGR valve only let's in exhaust gases in conditions when the car engine is not idling or when it does not require high combustible fuel concentration. This ensures optimum performance when RPM demands are high and prevents a rough performance when the engine is idling. Modern EGR valves are electronically operated.
In case the EGR valve malfunctions, engine efficiency drops down drastically. The biggest problem is caused when the EGR valve stays stuck open and messes up engine's efficiency. In such a situation, engine cylinders get flooded with exhaust gases, leading to a reduction in oxygen availability. This compromises the engine function totally. That is why a faulty EGR valve needs immediate replacement. Read more on car parts.
EGR Valve Replacement Instructions
Now let us look at how to replace EGR valves that are beyond repair. Replacing EGR valves is a task that can be carried out quite easily, if you are willing to apply yourself. The tools you'll need to carry out EGR valve replacement are a socket set, wrench, screwdriver, a specialized tool called carburetor cleaner and a small drill bit. Along with these, you'll need a new EGR valve and a new gasket that accompanies it.
Firstly, disconnect car battery and locate the position of EGR valve. Next you need to make some more disconnections. Remove the vacuum hose, air supply hose and rest of the electrical accessories, using a screwdriver.
To detach the EGR valve unit, you'll need to remove the bolts that keep it in place. Using a wrench, remove these EGR valve mounting bolts. Observe the valve and make sure that it is totally beyond repair. If it is, then go ahead and replace it with a new valve, along with a new gasket if needed. Mount the bolts back in place to secure the valve in position. Next, you need to retrace your actions and replace all the electrical accessories and components that you removed initially. Reconnect the air hose and restore other connections. Restore the car battery connection. This completes the EGR valve replacement procedure.
EGR valves are fitted in gasoline (petrol) and diesel engine assemblies of most cars today. They are an important modification made to car engines, in an effort to make them eco-friendly. Most importantly, EGR valve technology reduces emissions, without compromising the engine efficiency substantially. Before we understand how EGR valves work, one needs to know why there was a necessity to develop such a device in the first place. This is what we discuss in the next section.
Need For EGR Valve
EGR technology was developed to counter the growing threat of mono nitrogen oxide (NOx) production which occurs during combustion in engines. When emitted in the air, these gases (NO and NO2) react with other volatile organic compounds to create photochemical smog which has a harmful effect on the respiratory system. These nitrogen compounds react with moisture in the atmosphere, to produce nitric acid which is a major component of the precipitation that occurs in the form of acid rain. The combustion engines are ideal sites for reaction of nitrogen and oxygen due to the high temperatures that exist inside, reaching and exceeding 1600o Celsius. So, the EGR valve technology was developed to counter this threat of NOx emissions from fuel combustion which contribute substantially to the overall air pollution. The key, to counter it, was to reduce the temperature at which combustion occurs in car engines. Let us see how the EGR valve based technology achieved this objective.
How EGR Valve Works?
As the name suggests 'Exhaust gas recirculation valves', first introduced in 1972, are used to feed back a portion of the exhaust gases emitted by the car engine, back to the combustion chamber. The addition of these volume of gases reduces the quantity of oxygen available for combustion. Also, the addition of exhaust gases made to the air-fuel mixture, increases its specific heat capacity.
Due to both these factors, the adiabatic flame temperature of combustion. That is, the dearth in oxygen and increase in heat capacity, lead to the combustion of a gases at lower temperature. This effectively reduces the amount of mono nitrogen oxide gases created and released. Generally 5% to 15% of the exhaust gases are fed back in spark ignited engines. In diesel engines, the exhaust gases are cooled before they are fed back to the engine.
The efficiency of the engine does get reduced but there is a switching mechanism in place to take care of that. When the engine has a high RPM demand (Wide Open Throttle Conditions) and is in full acceleration mode, the EGR valve action is stopped and exhaust gases are no longer fed back to the engine. This ensures that the engine efficiency is not compromised when the RPM demands are high. It is also turned off when the engine is idling as it can destabilize the engine. Only in the region of mid acceleration, where the engine is between the two extreme conditions of full throttle and idle, does the EGR valve come into play. In modern cars, the action of the EGR valve is controlled by electronic engine controls mechanism.
How to Clean EGR Valve
Controlling emission of polluting gases from a car exhaust was a major challenge for designers of the automobile technology. One of the technological breakthroughs that emerged out of attempts made to control this emission is the EGR (Exhaust Gas Recirculation) mechanism fixed in car engines. In this article, I mainly talk about how to clean EGR valve to ensure its peak performance.
Automotive troubleshooting is a complex task that involves a multitude of small tune up jobs. Dirt, dust, heat and friction are the prime damaging agents of a car's interior mechanism. Car maintenance is all about taking precautions that these destructive agents are kept at bay. That is why knowing small jobs like how to clean EGR valves is essential. Before I share EGR valve cleaning instructions, let us understand the function of an EGR valve and why is it essential that it is cleaned periodically!
About EGR Valves
The concept of 'Exhaust Gas Recirculation' evolved out of the need to restrain the emission of nitrogen oxide compounds from a car's exhaust. Nitrogen oxide compounds are poisonous gases that can cause adverse effects on many biological systems that they come in contact with besides causing smog. Smog reduces visibility. That is why it was important that the emission of these gases be reduced. It is copiously produced in high temperature conditions, inside an engine, in a high concentration mixture of nitrogen and oxygen. Automobile engineers developed the EGR valve mechanism to nip the problem of nitrogen oxide production in the bud.
This was achieved in the following manner using a feedback mechanism. A portion of the exhaust gases are fed back to the engine's combustion chambers. This causes a drop in the temperature of the gasoline-air mixture and reduces the production of nitrogen oxide compounds. The EGR valve's function is to control when and how this feedback is supplied to the engine. The exhaust gases are not fed back when the engine is in high RPM mode or when it is almost idling. This ensures that the car engine's efficiency is not compromised. Thus the EGR valve's functioning is crucial for maintenance of engine efficiency.
EGR Valve Cleaning Instructions
Now that we know the functioning of the EGR valve, let us see why it's important that it is cleaned periodically. The EGR valve can cause a fall in engine efficiency and seriously compromise fuel economy of a car, due to carbon deposition and blocking caused by particulate matter. Clogging can can cause the diaphragm inside the valve to fall into disrepair. That is why it is important that you know how to clean EGR valves and perform the cleaning job once a year. Here are generic instructions on how to clean EGR valves. You will require a wrench set, socket set, scratch awl and phillips screwdriver for the job.
* Disconnect the car battery's negative terminal after which you need to do is to open the car hood and locate the EGR valve. It usually lies on the engine side and has a vacuum hose on top and an electrical connector. Refer to your car manual if you are not able to locate it.
* Remove the vacuum hose and electrical connector.
* Remove the pipe that connects to the EGR valve bottom.
* Then remove the entire EGR valve assembly by unscrewing the nuts holding it to the engine and the gasket, using wrenches. Now you can work on the EGR valve.
* Disconnect the solenoid that is usually attached to at the top of the valve, with a screwdriver.
With the help of a scratch awl, clean the bottom passage of the valve mechanism. This will get rid of the carbon deposits inside. Also clean the pipe attached to it. In case the EGR valve gasket is damaged, replace it. Otherwise just clean it. That's it. You have finished cleaning the EGR valve. Rest of the job is putting it back as it was. To do this, you must retrace your steps and go in reverse, by connecting the solenoid, pipe, vacuum hose, electrical connector and then reattach the EGR valve in its place in the proper reverse order. With that your cleaning job is finished entirely. Reconnect the car battery.
Emission control is a major concern for the automobile industry for a long time now. There have been many innovations in automobile technology, that have helped in bringing down emission and air pollution levels today. One such innovation is the EGR (Exhaust Gas Recirculation) valve technology. This article is aimed at explaining how to replace EGR valve in cars, which is a permanent fixture in most cars today.
What is EGR Valve?
For those who came in late, let me give you some background on exhaust gas recirculation technology, before we go into EGR valve replacement procedure. EGR technology was developed out of the need to reduce nitrogen oxide emissions from automobiles. To achieve this objective, a feedback mechanism was developed that could indirectly reduce nitrogen oxide emissions. This technology reduces nitrogen oxide emission by inhibiting the very process that leads to its creation. The technology works in the following manner. A portion of the exhaust gases emitted from car engine is fed back to combustion cylinder of the car engine.
This exhaust gas feedback displaces the combustive mixture of gases by volume and leads to a drop in the heat of combustion generated in every cycle. Without compromising to a great degree on the pressure generated in the cylinder, the combustion cycle occurs at a lower temperature. Nitrogen oxide compounds are formed faster from a high temperature mixture of oxygen and nitrogen. Since, exhaust gas recirculation valves reduce the combustion temperature in combustion cylinder, comparatively lesser amount of nitrogen oxide is created, which is responsible for creating smog.
EGR valves are fitted in the engine assembly to establish and control this feedback mechanism. The EGR valve only let's in exhaust gases in conditions when the car engine is not idling or when it does not require high combustible fuel concentration. This ensures optimum performance when RPM demands are high and prevents a rough performance when the engine is idling. Modern EGR valves are electronically operated.
In case the EGR valve malfunctions, engine efficiency drops down drastically. The biggest problem is caused when the EGR valve stays stuck open and messes up engine's efficiency. In such a situation, engine cylinders get flooded with exhaust gases, leading to a reduction in oxygen availability. This compromises the engine function totally. That is why a faulty EGR valve needs immediate replacement. Read more on car parts.
EGR Valve Replacement Instructions
Now let us look at how to replace EGR valves that are beyond repair. Replacing EGR valves is a task that can be carried out quite easily, if you are willing to apply yourself. The tools you'll need to carry out EGR valve replacement are a socket set, wrench, screwdriver, a specialized tool called carburetor cleaner and a small drill bit. Along with these, you'll need a new EGR valve and a new gasket that accompanies it.
Firstly, disconnect car battery and locate the position of EGR valve. Next you need to make some more disconnections. Remove the vacuum hose, air supply hose and rest of the electrical accessories, using a screwdriver.
To detach the EGR valve unit, you'll need to remove the bolts that keep it in place. Using a wrench, remove these EGR valve mounting bolts. Observe the valve and make sure that it is totally beyond repair. If it is, then go ahead and replace it with a new valve, along with a new gasket if needed. Mount the bolts back in place to secure the valve in position. Next, you need to retrace your actions and replace all the electrical accessories and components that you removed initially. Reconnect the air hose and restore other connections. Restore the car battery connection. This completes the EGR valve replacement procedure.
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