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

float bowl

fuel

atmosphericpressure

ventfuel

nozzle

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