exhaust

Exhaust refers to the mixture of gases produced by combustion and the system that channels those gases away from the source. In vehicles, the exhaust system collects spent combustion gases from the engine, guides them through a sequence of components, and releases them to the atmosphere while reducing noise and emissions.

Core components typically include the exhaust manifold, a downstream exhaust pipe, a catalytic converter for pollutant reduction, a muffler or resonator for noise control, and a tailpipe that ends at the rear of the vehicle. Modern systems also include oxygen sensors to monitor exhaust composition and adjust engine controls, and may incorporate other emissions-control devices such as exhaust gas recirculation valves.

Operation involves the exhaust gases traveling from the engine through these components. The muffler impedes sound waves; the catalytic converter lowers pollutants like nitrogen oxides, carbon monoxide, and hydrocarbons through chemical reactions. Sensors provide feedback to the engine control unit to optimize combustion and emissions.

Exhaust gases primarily consist of nitrogen, carbon dioxide, and water vapor under normal operation, with small amounts of CO, NOx, and hydrocarbons. Environmental standards regulate these emissions, and catalytic converters, particulate filters, and other devices help meet limits. Back pressure, material durability, and corrosion resistance influence design and maintenance.

Maintenance focuses on preventing leaks, ensuring secure mounting, and replacing worn components. Damaged exhaust systems can increase noise, decrease efficiency, or allow toxic fumes to enter the cabin. Regulations and inspections vary by jurisdiction.