ASVAB Automotive Information Practice Test 634461

Questions 5
Topics Camshaft, Control Arms, Solenoid, Thermostat, Wheel Hub

Study Guide

Camshaft

The camshaft is linked to the crankshaft through a timing belt and regulates the opening and closing of the intake and exhaust valves in each cylinder in time with the motion of the piston. An engine designated OverHead Camshaft (OHC) locates the camshaft in the cylinder head. An engine with Double OverHead Camshaft (DOHC) has two camshafts, one to regulate the intake valves and one to regulate the exhaust valves.

Control Arms

Control arms (upper and lower) connect a vehicle's suspension to the frame. The connection to the wheels is through ball joints which allow the control arms to turn and move up and down simultaneously. The frame connection uses bushings.

Solenoid

The cylindrical solenoid is a relay that safely connects the high amperage battery to the starter motor when the ignition key is turned. This current then allows the engine to turn at a high enough speed to start.

Thermostat

The thermostat controls coolant (and, through it, engine) temperature by regulating the flow of coolant through the radiator. A bypass tube allows coolant to bypass the radiator and flow back into the water pump when its temperature is low enough that the thermostat is closed.

Wheel Hub

The wheel hub is the mounting point for the wheel and tire assembly. The wheel hub can rotate while being held stable by the steering knuckle which applies the motion of the control arms to the wheels.