Automotive Engines Part 5 (Induction)

Induction The term “induction” applies to the pathway for fuel and air to enter the combustion chamber. Including: – Carburetion – Fuel Injection – Manifolds

Carburetors Rely on the Venturi Vacuum principle Rated in CFM 3 Common Styles – 1 Barrel – 2 Barrel – 4 Barrel (square bore/spread bore)

Venturi Vacuum

1 Barrel (200 – 400 CFM)

2 Barrel (350 – 500 CFM)

4 Barrel (400 – 1150 CFM)

Square Bore Vs. Spread Bore

Fuel Injection Fuel injection atomizes the fuel by forcibly pumping it through a small nozzle under high pressure (15-90 psi). – Throttle Body Injection – Port Fuel Injection

Throttle Body Injection 1 or 2 Injectors for engine

Port Fuel Injection An injector per cylinder aimed at the port opening.

Typical Injector

Intake Manifold “Wet” for Carbureted applications “Dry” for Injected applications Older manifolds were made from Cast Iron Modern manifolds are made from Aluminum Future manifolds will almost always be made of plastic (vinyl, phenolic resin, etc.)

Carbureted Intake Manifold

Injected Intake Manifold