Exhaust System

Parts Of The Exhaust System: 

• Exhaust Manifold 

  • Closest to engine block and first step of emissions process—larger vehicles may have two 

  • Collects fumes released from cylinders and burns any unburnt gas 

  • Made of stainless steel, aluminum, and cast iron to handle high temperatures 

  • Directs gases to catalytic converter  

• Oxygen Sensor 

  • All modern engines have at least 2 

  • First is found within exhaust manifold and measures amount of oxygen present in the exhaust fumes 

    • Determines if more or less fuel is needed to achieve optimum efficiency and performance 

  • Other sensors are typically in the catalytic converter 

• Catalytic Converter 

  • Two types of converters 

    • Two-Way 

      • Typically on older vehicles 

      • Only reduce carbon monoxide and hydrocarbon 

    • Three-Way 

      • On newer vehicles  

      • Reduces nitrogen oxide as well  

  • Gases come from manifold and a combination of catalysts are used to reduce the emissions 

    • Catalyst materials include 

      • Platinum, palladium, and rhodium 

    • Coated onto ceramic or metallic substrate to allow for large surface area for the reaction to occur. 

  • Hydrocarbons and carbon monoxide are turned into water and carbon dioxide while nitrogen oxides are reduced in the process 

  • Required on all cars to meet emission regulations 

• Exhaust Pipes 

  • Numerous pipes to connect all components in the system 

  • Run along the length of car on the underbody 

  • Pipe designs 

    • Straight pipe 

      • Pipe that leads straight from engine to tailpipe 

    • Header  

      • Series of pipes that merge into one larger pipe  

      • Used in higher performance engines 

    • Dual exhaust  

      • Two exhaust pipes that run from engine to tailpipe 

• Muffler and Resonator 

  • • Added to absorb majority of sound in the system 

    • Resonator is added when the muffler isn't enough on its own 

    • Focuses specifically on high-pitches, humming, and buzzing 

• Work together to dampen sound 

• Exhaust Outlet 

  • The end of the pipe line where the product is expelled 

  • Also known as tailpipe  

  • Tailpipe Designs 

    • Straight cut 

      • Simplest design  

      • Straight from exhaust system to back of vehicle 

    • Rolled edge 

      • Rolled edge at end of pipe 

      • Popular because it looks stylish 

    • Turn down 

      • Pipe that faces downwards  

      • Directs gases down 

  • Usually at the end and sometimes have dual outlets 

  • Trucks may position them on the sides instead