# How Rudolf Diesel's Engine Works

> Rudolf Diesel's 1898 patent describes a highly efficient engine that ignites fuel using the heat generated by compressing air rather than using a spark plug.

- **Patent:** US 608845
- **Original title:** Internal-combustion engine
- **Owner:** Rudolf Diesel
- **Granted:** 1898
- **Status:** Active
- **Times cited:** 10
- **Field:** automotive, mechanical, energy

## What it does

The engine operates by drawing in air and compressing it to such a high pressure that the temperature rises significantly. Once the air is hot enough, fuel is injected directly into the cylinder. The fuel ignites spontaneously upon contact with the superheated air, eliminating the need for an external ignition source like a spark plug.

## What it does NOT cover

- Does not cover engines that use spark plugs for ignition.
- Does not cover engines that mix fuel and air before compression.
- Does not cover external combustion engines like steam engines.

## The clever bit

Instead of trying to ignite a fuel-air mixture with a spark, Diesel used the laws of thermodynamics to turn the compression stroke itself into the ignition source.

## Real-world examples

1. Modern semi-truck engines
2. Diesel-powered locomotives
3. Marine ship propulsion systems
4. Construction equipment like excavators

## Why it matters

This invention fundamentally changed transportation by creating a more efficient alternative to the gasoline engine. It enabled the development of heavy machinery, long-haul trucking, and maritime shipping by providing superior torque and fuel economy.

## Frequently asked questions

### What does How Rudolf Diesel's Engine Works cover?

Rudolf Diesel's 1898 patent describes a highly efficient engine that ignites fuel using the heat generated by compressing air rather than using a spark plug.

### Who owns patent US 608845?

Rudolf Diesel owns this patent, granted in 1898.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 608845 cited by?

This patent has been cited by 10 later patents that build on its ideas.

### What problem does this patent solve?

This invention fundamentally changed transportation by creating a more efficient alternative to the gasoline engine. It enabled the development of heavy machinery, long-haul trucking, and maritime shipping by providing superior torque and fuel economy.

### What does this patent NOT cover?

Does not cover engines that use spark plugs for ignition.

**Full plain-English explainer:** https://patentbrief.org/patent/us/608845/diesel-engine

**Original patent:** https://patents.google.com/patent/US608845

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [George Selden's 1895 Patent for a Road Engine](https://patentbrief.org/patent/us/549160/selden-automobile-patent) — George Selden's 1895 patent describes a 'road engine,' a precursor to the automobile, focusing on a combined engine and vehicle design.
- [How the Wankel Rotary Engine Works](https://patentbrief.org/patent/us/2988008/wankel-rotary-engine) — A 1957 invention by Felix Wankel that replaces heavy, moving pistons with a triangular rotor spinning inside a chamber to create power.
- [How Alfred Nobel Stabilized Nitroglycerin with Dynamite](https://patentbrief.org/patent/us/78317/dynamite-nobel) — Alfred Nobel's 1868 patent for dynamite, which made the volatile liquid explosive nitroglycerin safe to handle by mixing it with an absorbent material.
- [How Ole Evinrude Invented the Modern Portable Outboard Motor](https://patentbrief.org/patent/us/1001260/outboard-motor-evinrude) — A 1911 patent for a compact, detachable marine engine that allowed small boats to be powered by a portable, gasoline-driven propeller unit.
- [John Gorrie's 1851 Patent for Artificial Ice Production](https://patentbrief.org/patent/us/8080/ice-machine-refrigeration-gorrie) — An 1851 patent by John Gorrie describing a mechanical process to create ice by compressing air and using it to cool water.