Key Components That Comprise Your Car’s Emission Control System
The combustion process that takes place in your car’s engine produces a number of emissions. These include carbon monoxide (which can be deadly), hydrocarbons (which pollute the environment), and oxides of nitrogen. Because of the pollution and health risk these compounds pose, the government passed legislation in 1977 limiting their output. The result was that automakers were forced to design emission control systems (ECS) for their vehicles.
Within a few years, car manufacturers had begun to create technology that allowed engines to adjust themselves, according to their emissions output. This included placing an oxygen sensor in the path of the exhaust leaving the engine. The sensor monitored the level of fuel, and delivered that information to the powertrain control module (PCM). The PCM would then adjust the amount of fuel sent to the cylinders.
Today’s vehicles are equipped with systems that are more robust. The PCM – essentially, a computer – monitors data from multiple sensors, and uses it to identify problems, and if possible, correct them. Below, we’ll take a closer look at the main components that comprise your car’s emission control system.
Catalytic Converter
This component marks the biggest breakthrough in the design of emissions systems. The exhaust from your engine flows through the pipes and into the catalytic converter. The part contains a filter media that has been coated with a special material. This material interacts with the emissions contained in the exhaust. Carbon monoxide is turned into water. Hydrocarbons are turned into carbon dioxide. As a result, the output that exits your tailpipe contains very few emissions.
The catalytic converter is designed to last for several years, usually up to 100,000 miles. But it can fail sooner if it is forced to work harder than it should. If the exhaust coming from your engine is especially “dirty,” the converter will need to work harder in order to clean it. This can place excess stress on the component until it eventually dies.
PCV And EGR Valves
Your vehicle’s ECS is designed to funnel some of the gases coming out of your cylinders back into the engine. There, they are burned along with the air-fuel mixture. The positive crankshaft ventilation (PCV) valve controls this process. When your car is idling, the valve allows a small amount of gases into the intake system. When you’re traveling at normal speeds, it allows more in.
The exhaust gas recirculation (EGR) valve performs a different, though related, function. Its job is to monitor the emissions going into the intake system, and adjusting the level to manage production of oxides of nitrogen. The higher the temperature inside the engine, the more oxides of nitrogen that are produced. However, the more exhaust the EGR valve allows in, the lower the combustion temperature becomes. The exhaust essentially has a dilutive effect on the air-fuel mixture.
Canister For Gasoline Vapors
Fuel evaporates even when it is sitting idle in the gas tank. The problem is, this evaporation allows vapors to escape into the atmosphere. In the 1970s, the government required automakers to install a control mechanism in the gas tank to catch these vapors before they could escape. This mechanism is a charcoal canister. Vapors are confined within, and released when you start your car. At that point, they are pulled into the engine, and burned with the air-fuel mixture.
When Trouble Codes Are Triggered
When problems develop in the emission control system, your powertrain control module will set a fault code. This code will be stored in the computer’s memory. The check engine light on your dashboard will alert you regarding the issue. Even though you can continue driving with a faulty ECS, you should have problems addressed as soon as the light goes on. Otherwise, your vehicle will allow excess emissions into the environment, and potentially place you and your passengers at risk.
Find the best Wichita used cars and Junction City Toyota car deals from conklincars.com
