Car-Tech News

What are EGR valves and how to find a replacement

In modern gasoline and diesel engines, EGR valves are used for accurate control of slurry combustion, to increase operational efficiency and to reduce the amount of nitrogen oxide and carbon-hydrogen.


The EGR valve is used that the mixture of fresh air and fuel introduced smaller, or larger quantity of exhaust gas, which are used to regulate combustion. Things are very simple. Too large an amount of oxygen produces a flame and a hot combustion rate of the mixture. In response to an increase of the temperature in the combustion chamber, an undesirable chemical reaction between oxygen and inlet air nitrogen, which are formed during toxic nitrogen oxides. As a result, in addition to increasing environmental pollution, due to the iteration with nitrogen, the same mixture in the engine remains less oxygen for the combustion of fuel, thus reducing energy, increasing the level of carbon-hydrogen. When the warm mixture has been added the appropriate amount of burnt exhaust gas, which contains no oxygen, there is a drop in combustion temperature and taking the parameters from the motor to normal.

In petrol engines, the EGR reduces the possibility of self-ignition. As a direct result, you can use a higher compression ratio and a different time point to give a more flexible engine. In diesel engines, it significantly reduces pounding noise when operated to a minimum.

EGR valve in reverse gasoline and diesel engines. When the diesel oil during operation to a fully open minimum and can provide up to 50 percent of the presence of combustion gases in the combustion chamber. Increasing the power and speed in the completely closed. For a change, the gasoline EGR valve is completely closed to a minimum and opens slowly with increasing force. However, the maximum share of exhaust gas is only 5-10 percent.

The EGR valve is subject to cancellation for obstruction of work, mainly due to the deposition of soot particles. The valve can remain completely open, completely closed, or may have a slow response. If the header is in the open position, the gasoline will cause poor n Idle performance, and the diesel will cause a reduction in the power and black smoke of the exhaust. If the EGR has been closed, it would cause excessive crushing on diesel engines and an increase in fuel consumption of petrol.

What to do?

When the EGR valve fails, the only actual replacement repair. It is advisable to always use a spare part of the high quality specifications fully meets the requirements of the factory. One of the largest and best spare parts manufacturers is a Delphi company. Their recommendation is that the replacement valves check thoroughly and clean if you need to connect the hoses and connectors.