ASVAB Automotive Information Practice Test 905081

Questions 5
Topics Actuators, Firing Order, Intake Manifold, Power Stroke

Study Guide

Actuators

Actuators receive signals from the powertrain control module and carry out adjustments needed based on the data the PCM received from the sensors.

Firing Order

The stroke cycle of an engine is governed by the crankshaft which serves to regulate the firing order of the cylinders. All cylinders are not on the same stroke at the same time and correct firing order is important to balance engine operation and minimize vibrations. A common firing order for four-cylinder engines is 1-3-4-2 which indicates that cylinders 1 and 3 fire (power stroke)together and cylinders 4 and 2 fire together.

Intake Manifold

The intake manifold distributes outside air to the intake ports on the cylinder heads. The intake air filter removes any airborne contaminants before the air enters the engine.

Power Stroke

During the power stroke, just before the piston reaches top dead center, the spark plug fires and ignites the compressed air-fuel mixture. The resulting expansion due to combustion pushes the piston back down the cylinder toward bottom dead center.