diesel engine

American  

noun

1. a compression-ignition engine in which a spray of fuel, introduced into air compressed to a temperature of approximately 1000° F (538° C), ignites at a virtually constant pressure.

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diesel engine British  

noun

1. a type of internal-combustion engine in which atomized fuel oil is sprayed into the cylinder and ignited by compression alone

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diesel engine Scientific  

/ dē′zəl /

1. An internal-combustion engine in which the fuel oil is ignited by the heat of air that has been highly compressed in the cylinder, rather than by a spark. Due to the need for the engine to withstand very high pressures, diesel engines are relatively heavy; however, they are relatively fuel-efficient, especially when running at low power.

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Etymology

Origin of diesel engine

First recorded in 1890–95

Example Sentences

The batteries will have about as much capacity as 200 Tesla Model 3s, and a 500-mile range without using the diesel engine.

From The Wall Street Journal • Jan. 15, 2026

"I feel like I'm more of a diesel engine sometimes where I need to get going first, then at some point I'll start playing good tennis. I have to play a preparation tournament."

From Barron's • Jan. 3, 2026

The main propulsion diesel engine automatically shut down after its cooling pumps lost power, and the ship lost steering.

From Seattle Times • May 15, 2024

While a fuel cell is comparable in size to a diesel engine, a battery big enough for long-haul trucks adds weight and size and cuts down on the total freight load the truck can deliver.

From Los Angeles Times • Apr. 24, 2024

They could hear the diesel engine out on the road, running on God knows what.

From "The Road" by Cormac McCarthy

Related Words

• diesel