What is the Function of a Car EGR Valve?

[VanRemington]

The function of a car EGR (Exhaust Gas Recirculation) valve is to allow a portion of the exhaust gases to recirculate back into the engine cylinders for combustion. This small amount of exhaust gas helps lower the combustion temperature in the cylinders. Since NOx (nitrogen oxides) are produced under high-temperature and oxygen-rich conditions, this process suppresses NOx formation, thereby reducing NOx emissions in the exhaust. Common causes of EGR valve failure include: 1. Poor quality of the valve itself; 2. Improper maintenance; 3. Low-quality fuel; 4. Aging—the EGR valve operates under high engine temperatures and, over time, deteriorates like valve cover gaskets and rubber seals. A faulty EGR valve cannot properly control the exhaust gas recirculation rate. Excessive exhaust gas entering the combustion chamber can negatively affect the ignition and performance of the air-fuel mixture, ultimately reducing engine power.

[JoshuaDella]

I often ponder over the various valves in car engines, and this exhaust gas recirculation (EGR) valve is actually a super important component, especially when it comes to controlling crankcase pressure. During engine operation, some gases from the combustion chamber leak into the crankcase, and their accumulation can lead to excessive pressure, which may cause oil seal leaks or damage to engine components. The EGR valve plays a role in exhaust regulation, redirecting those unburned exhaust gases back to the intake manifold, allowing them to be reignited in the next combustion cycle. This not only reduces pollutant emissions, protecting the environment, but also maintains smooth engine operation and extends its lifespan. If this part fails, the consequences can be significant, such as noticeable idling vibrations, excessive emissions, or even worsening odors inside the car. I've seen this issue in many older vehicles—if not repaired promptly, overall performance can be affected. Therefore, checking the connections and hoses for blockages every six months is a good habit, especially in high-temperature environments.

[BriellaAnn]

When driving my old car on a long trip, I noticed a strong oily smell coming in during acceleration. Upon inspection, I found that the PCV (Positive Crankcase Ventilation) valve was stuck and hadn't been properly repaired. Its core function is to manage crankcase pressure, preventing excessive gas buildup that could blow out seals, while redirecting these exhaust gases back into the intake system for combustion—avoiding fuel waste and air pollution. For daily driving, it acts like a small environmental guardian—inconspicuous yet indispensable. When faulty, it can cause unstable idling, increased fuel consumption, and accelerate engine carbon buildup. I recommend car owners periodically check under the hood to ensure this small valve operates correctly, with no aging or cracked connecting hoses. If replacing it, selecting the correct part number is crucial—wrong matches may backfire and disrupt engine performance. Never neglect this component long-term, as it directly impacts both safety and cost savings!

[Emersyn]

Having focused on automotive emissions for years, I've found that the PCV valve plays a pivotal role in the environmental protection chain. Designed to capture unburned gases from the crankcase and recirculate them into the combustion chamber for reuse, it significantly reduces the emission of harmful pollutants such as hydrocarbons and nitrogen oxides, which greatly contributes to urban air purification. From personal experience, maintaining this component can improve fuel efficiency and reduce sludge buildup. In short, it ensures cleaner vehicle operation.