Speak Izy : Cars | Tech | Lifestyle
A regular fuel (petrol or diesel) is made up of hydrocarbons. That means atoms of Hydrogen and Carbon arranged in various proportions form molecules of petrol or diesel. Essentially, after the treatment of natural resources, the end product we get is the hydrocarbon chains. Depending on the number of carbon atoms and length of the chain, it is either classified as petrol or diesel.
During the combustion phase inside the cylinder of the engine, the air-fuel mixture almost never burns completely. Complete combustion is referred to as when the end products of the combustion are Carbon Dioxide and Water. But during the operation of an internal combustion engine, due to various reasons and factors, complete combustion almost never occurs. What that translates to is there are numerous undesirable and toxic gases present in the exhaust system of an engine. These gases are not only bad for environmental pollution but also cause severe health hazards if people inhale these. Being toxic and poisonous in nature, these gases are allowed in minute amounts according to the BS6 emission norms, which came into effect in 2019.
This is where the Catalytic Converters come into the picture. The Catalytic Converters react with the harmful exhaust gases and the resultants formed are harmless gases, that are normally found in the atmosphere. This includes conversion of carbon monoxide to carbon dioxide and oxides of nitrogen to nitrogen and oxygen gases. The unburnt fuel (hydrocarbons) are also reduced to carbon dioxide and water and removed from the engine into the atmosphere. All the gases are ultimately the same gases that are found otherwise in the atmosphere as well. This is the sole purpose of the catalytic converters in the vehicles. Depending on the complexity, there are various forms of catalytic converters.
A Selective Catalytic Converter requires an additional storage tank filled with Urea. After the two-way catalytic converter, there is an injector that is controlled by the ECU (Electric Control Unit) of the vehicle. The ECU signals the injectors to spray a particular amount of urea into the exhaust manifold depending on the data that the ECU receives from the sensors of the engines. Accordingly, the amount of urea required to convert oxides of nitrogen into individual Nitrogen and Oxygen atoms is injected. Because this system is a bit complicated and requires additional storage and refilling of urea in the vehicle, it is a bit expensive and therefore, used only in above the entry-level budget cars.
While catalytic converters don’t eliminate air pollution, they can be instrumental in reducing immediate, localized air pollution, including pollution from roadways. Catalytic converters also work best when they’re warm, which takes about 10-15 minutes of driving or idling. This means your car may still churn out emissions for the first few minutes of a trip. The main aim for an exhaust system is to get the exhaust gasses away from the engine in a smooth and swift fashion, with restrictions and expansions like a large catalytic converter only causing turbulence and therefore disturbed, slower airflow. Sport cats do their best to solve this issue by decreasing the chamber size and creating a much smoother surface within the chamber to allow for the gasses to flow quicker and easier through it.
To keep emissions down, the ceramic matrix within the honeycomb construction is much finer than in a normal cat, thus making sure that the catalysts can effectively convert the relevant nasties to where they need to be to meet emission rules. Small increases in power can be achieved by switching to a sports cat, with the engine cycle being freed-up to maximise its efficiency.
