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  2. Valvetrain - Wikipedia

    en.wikipedia.org/wiki/Valvetrain

    A valvetrain is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. [1] The intake valves control the flow of air/fuel mixture (or air alone for direct-injected engines) into the combustion chamber, while the exhaust valves control the flow of spent exhaust gases out of the ...

  3. Component parts of internal combustion engines - Wikipedia

    en.wikipedia.org/wiki/Component_parts_of...

    In piston engines, the valves are grouped into 'inlet valves' which admit the entrance of fuel and air and 'outlet valves' which allow the exhaust gases to escape. Each valve opens once per cycle and the ones that are subject to extreme accelerations are held closed by springs that are typically opened by rods running on a camshaft rotating ...

  4. Exhaust brake - Wikipedia

    en.wikipedia.org/wiki/Exhaust_brake

    An exhaust brake is a valve which essentially creates a back-pressure in the exhaust system, which applies enough force onto the engine's pistons to slow the engine. In most cases, an exhaust brake is so effective that it can slow a heavily-loaded vehicle on a downgrade without ever applying the vehicle’s service brakes.

  5. Crankcase ventilation system - Wikipedia

    en.wikipedia.org/wiki/Crankcase_ventilation_system

    A second function of the PCV valve is to act as a flame arrester and to prevent positive pressure from the intake system from entering the crankcase. This can happen on turbocharged engines or when a backfire takes place, and the positive pressure could damage the crankcase seals and gaskets, or even cause a crankcase explosion.

  6. Rocker arm - Wikipedia

    en.wikipedia.org/wiki/Rocker_arm

    The most common use of a rocker arm is to transfer the motion of a pushrod in an overhead valve (OHV) internal combustion engine to the corresponding intake/exhaust valve. In an OHV engine the camshaft at the bottom of the engine pushes the pushrod upwards. The top of the pushrod presses upwards on one side of the rocker arm located at the top ...

  7. Air suction valve - Wikipedia

    en.wikipedia.org/wiki/Air_suction_valve

    Its function is the same, using a vacuum at the intake to trigger a valve that pulses atmospheric air into the exhaust. The original "iron barrel" style engine did this with a hose from the PAV going to the exhaust pipe, the newer (2003–2009) AVL aluminum engine pulses the gas directly into the exhaust port on the head of the engine itself.

  8. Valve timing - Wikipedia

    en.wikipedia.org/wiki/Valve_timing

    Valve timing diagram for a 4-stroke engine. With traditional fixed valve timing, an engine will have a period of "valve overlap" at the end of the exhaust stroke, when both the intake and exhaust valves are open. The intake valve is opened before the exhaust gases have completely left the cylinder, and their considerable velocity assists in ...

  9. Exhaust manifold - Wikipedia

    en.wikipedia.org/wiki/Exhaust_manifold

    A full oscillation of the Helmholtz resonance occurs before the exhaust valve is closed, and to increase low-speed torque, large amplitude exhaust pressure waves are artificially induced. This is achieved by partial closing of an internal valve within the exhaust—the EXUP valve—at the point where the four primary pipes from the cylinders join.