pakoputkisto

The pakoputkisto (exhaust system) of a vehicle collects combustion gases from the engine and directs them away from the cabin, while dampening noise and reducing pollutants.

A typical pakoputkisto includes an exhaust manifold or headers attached to the cylinder head, a network of downpipes and midpipes, a catalytic converter, a resonator, a muffler, and a tailpipe. Oxygen sensors monitor gas composition for the engine control unit. Mounting hardware, heat shields, and flexible sections accommodate thermal expansion and vibration.

Gas flow begins at the exhaust manifold, through the catalyst where pollutants are reduced, then through the resonator and muffler to lower sound levels, and finally out the tailpipe. Modern systems may feature multiple catalysts and sensors, and may include a diesel particulate filter in diesel applications.

There are stock OEM exhausts designed for noise, emissions, and reliability, and aftermarket variants such as cat-back, axle-back, or header-back systems for performance or sound changes. Materials commonly used include stainless steel, aluminized steel, or mild steel with protective coatings.

Maintenance involves checking for leaks, rust, loose clamps, or broken hangers, replacing gaskets, inspecting the catalytic converter for damage, and ensuring proper seals to avoid carbon monoxide entering the cabin. A noisy or leaking pakoputkisto can pose safety risks.

Regulations govern emissions control devices, catalytic converters, and noise levels. Tampering with the exhaust system is illegal in many jurisdictions. Environmental and safety considerations drive design and material choices.