ASVAB Automotive Information Practice Test 248128

Questions 5
Topics Air-Fuel Mixture, Exhaust Manifolds, Oil Pan, Springs, Water Jacket

Study Guide

Air-Fuel Mixture

The stoichiometric ratio defines the proper ratio of air to fuel necessary so that an engine burns all fuel with no excess air. For gasoline fuel, the stoichiometric ratio is about 14.7:1 or for every one gram of fuel, 14.7 grams of air are required. Too much air results in a lean air-fuel mixture that burns more slowly and hotter while too much fuel results in a rich mixture that burns quicker and cooler.

Exhaust Manifolds

The cast iron exhaust manifolds collect engine exhaust gas from multiple cylinder exhaust valves and deliver it to the exhaust pipe. Exhaust manifolds can be generic or specially tuned (header pipes) to the engine. Header pipes deliver higher performance but are more expensive and less durable.

Oil Pan

The oil pan contains the engine oil reservoir of from four to six quarts of oil and feeds the oil pump through the oil pickup tube. An oil strainer floats at the top of the oil in the oil pan and screens debris from the oil before feeding it to the oil pump.

Springs

Suspension springs are made with wide gap coils of rigid steel cable and both hold the vehicle chassis up off the ground and absorb energy from wheel movement making for a smoother ride.

Water Jacket

A water jacket is a coolant-filled casing that allows heat transfer from the engine block and cylinder heads to the liquid coolant.