Oilers/Plant Tenders (HHC) Civil Service Practice Exam

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Prepare for the Oilers/Plant Tenders (HHC) Civil Service Exam. Enhance your skills with flashcards and multiple-choice questions, each offering hints and clear explanations. Ace your exam with confidence!

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In a diesel engine, what is responsible for igniting the fuel?

Electric spark
Heat of compression
Laser ignition
Fuel additives

The correct answer is: Heat of compression

In a diesel engine, the ignition of fuel occurs through the heat of compression. This process is a fundamental characteristic of how diesel engines operate. When air is drawn into the engine's cylinder, it is compressed to a very high pressure, which significantly raises its temperature. Once the temperature reaches a critical point, the fuel is injected into the cylinder. The high temperature of the compressed air ignites the diesel fuel without the need for a spark plug. This method of ignition is what differentiates diesel engines from gasoline engines, which typically rely on an electric spark to initiate combustion. The use of heat of compression not only allows for higher efficiency but also enables diesel engines to run on various types of fuel. Thus, the heat generated from compressing air in a diesel engine is essential for the combustion process, making it the correct answer.