What is the major difference between diesel and gasoline engines?

What is the major difference between diesel and gasoline engines?

• A. Cylinder arrangement
• B. Ignition process
• C. Cooling system
• D. Emission controls

Answer: (B)

Fuel ignition method sets the difference. Gasoline engines use spark ignition—a spark plug lights a premixed air–fuel charge. Diesel engines rely on compression ignition: air is compressed to a very high temperature and fuel is injected so it self-ignites without a spark. This fundamental difference drives how the engines are designed and operated, including compression ratios and fuel delivery. Cylinder arrangement, cooling systems, and emission controls can vary, but the ignition method is the defining distinction.

Fuel ignition method sets the difference. Gasoline engines use spark ignition—a spark plug lights a premixed air–fuel charge. Diesel engines rely on compression ignition: air is compressed to a very high temperature and fuel is injected so it self-ignites without a spark. This fundamental difference drives how the engines are designed and operated, including compression ratios and fuel delivery. Cylinder arrangement, cooling systems, and emission controls can vary, but the ignition method is the defining distinction.