Air enters through the air cleaner and passes through the carburetor to be mixed with the correct amount of fuel. Air-fuel mixture then passes through the inlet manifold, and enters the cylinders.
Electronic fuel injection is controlled by an electronic control unit. It has replaced the carburetor on most modern engines. EFI engines run more smoothly, with lower fuel consumption and emissions, and more power than carbureted engines.
Diesel engines draw in air only. Speed and power is controlled by the amount of fuel injected at the end of the compression stroke. 2-stroke diesels use a blower for induction and to improve scavenging.
An exhaust system must reduce engine noise and discharge exhaust gases safely away from the vehicle. An efficient exhaust system can improve engine performance.
