What type of engine is specifically designed to run on diesel fuel?

A diesel engine is specifically designed to operate using diesel fuel, which is a type of fuel derived from crude oil that has different combustion characteristics compared to gasoline. Diesel engines utilize a higher compression ratio to ignite the fuel, allowing for greater thermal efficiency and torque, making them popular in heavy-duty applications such as trucks and industrial machinery. The engine’s design includes fuel injectors that spray diesel into the combustion chamber at high pressure, and the ignition occurs without the need for spark plugs, as the high compression heats the air to a temperature sufficient to ignite the fuel.

In contrast, gasoline engines rely on a different combustion process using spark ignition and are designed to run on gasoline. Hybrid engines combine both gasoline and electric power without being dedicated solely to diesel fuel. Electric engines operate using electric power and do not rely on any type of liquid fuel for propulsion. Thus, the distinct functioning and fuel requirements of the diesel engine make it the correct answer in this context.