ASVAB Automotive Information Practice Test 449416

Questions 5
Topics Engine Block, Firing Order, Power Brakes, Radiator, Shock Absorbers

Study Guide

Engine Block

The engine (or cylinder) block is the large casing that contains the cylinders and many of the internal components of the engine.

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.

Power Brakes

Power brakes multiply the force a driver applies to the brake pedal using a vacuum booster connected to the engine intake manifold. This provides for much higher hydraulic pressure in the braking system than could be generated by the driver alone. Antilock brakes (ABS) use speed sensors and adjust the brake pressure at each wheel to prevent skidding and allow the driver more steering control in slippery conditions.

Radiator

The radiator is responsible for tranferring heat from the coolant to the outside air. Radiator hoses transfer coolant to and from the engine to the radiator and a radiator cap maintains pressure in the cooling system to increase the boiling point of the coolant mixture and thus allow it to absorb more heat.

Shock Absorbers

Because a compressed spring will ex­tend violently, shock absorbers must be used to dampen the spring’s compression and extension cycles. Struts combine the spring and shock into one unit