Skip to main content

four-stroke engine

four-stroke engine Engine in which the operation of each piston is in four stages, each stage corresponding to one movement of a piston along a cylinder. The stages are: induction, in which the fuel-air mixture enters the cylinder; compression; expansion, in which the exploding mixture forces the piston along the cylinder; and exhaust. This system is called the four-stroke cycle, or the Otto cycle, after its inventor, Nickolaus Otto (1832–91), and is used by many internal combustion engines, including diesel engines.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"four-stroke engine." World Encyclopedia. . 18 Mar. 2018 <>.

"four-stroke engine." World Encyclopedia. . (March 18, 2018).

"four-stroke engine." World Encyclopedia. . Retrieved March 18, 2018 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.