ASVAB Automotive Information Practice Test 974921

Question 2 of 5
Internal Combustion

Combustion is the burning of an air-fuel mixture to provide energy. It requires the presence of air, fuel, and a heat source to ignite the air-fuel mixture. In the internal combustion engine that powers automobiles and trucks the combustion happens inside the engine utilzing a fuel like gasoline, diesel fuel, or natural gas.

Which of these is not necessary for combustion?

air

fuel

heat source

accelerant