ASVAB Automotive Information Practice Test 625451

Questions 5
Topics Air-Fuel Mixture, Exhaust Stroke, Independent Suspension, Solenoid, Transfer Case

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 Stroke

During the exhaust stroke, just before the piston reaches bottom dead center the exhaust valve opens. The resulting gases from combustion are then pushed out through the exhaust valve as the piston travels up the cylinder to top dead center, completing stroke four of the four-stroke piston cycle.

Independent Suspension

Most modern cars use an independent suspension system on the front wheels. This setup allows each of the wheels on an axle to move independently in response to road level variations. Independent suspension offers much better handling and stability when compared to a rigid axle suspension at the cost of being structurally weaker and more costly to maintain.

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.

Transfer Case

The transfer case splits engine power between the front and rear axles of four-wheel drive vehicles.