Which component is primarily responsible for reducing harmful emissions in an internal combustion engine?

The catalytic converter is the component primarily responsible for reducing harmful emissions in an internal combustion engine. Its primary function is to convert harmful gases produced during combustion, such as carbon monoxide, hydrocarbons, and nitrogen oxides, into less harmful emissions before they are released into the atmosphere.

The catalytic converter uses a chemical reaction facilitated by precious metals, like platinum, palladium, and rhodium, to transform these harmful substances into carbon dioxide and nitrogen. This conversion significantly decreases the engine's environmental impact and helps meet regulatory emission standards.

While the fuel injector plays a crucial role in delivering the correct amount of fuel to the engine for efficient combustion, it does not directly reduce emissions. The air filter helps maintain engine performance by preventing dirt and debris from entering the engine, but it does not impact emissions directly. The exhaust manifold collects exhaust gases from the engine cylinders and directs them to the exhaust system, but like the fuel injector and air filter, it does not alter the composition of the emissions themselves. Each of these components has an essential function, but the catalytic converter specifically targets the reduction of harmful emissions.