The 2-stroke engine was invented in 1881 by Englishman Dugald Clerk. The most current version of this type of engine, known as a “pump housing” and lights, was designed ten years later by another Englishman, Joseph Day.
The 2-stroke engine has so far been used for applications that take advantage of its specific power higher than that of the 4-stroke engine.
This article is devoted to the fields of so-called “lightweight” 2-stroke engines. These are applications requiring compact and light engines, and controlled ignition (therefore using gasoline-type fuels): from very small model-making engines (from 2 cm3 displacement), through small generators, portable tools (chainsaws, brush cutters, etc.), 2 and 3 wheelers, snow scooters, marine outboard motors (which can reach automobile-size displacements).
During the 1990s, a new generation of 2-stroke gasoline direct injection engines was developed and gradually met increasing environmental requirements in terms of reducing pollutant emissions. Significant associated progress in terms of yield has also resulted.
In 2021, the new generation light 2-stroke engine therefore remains mainly present in markets where its advantages are undeniable compared to its 4-stroke competitor such as portable tools, snow scooters, tactical drones. It is also mainly present in the other end of the range of thermal engines, that of heavy engines and in particular large 2-stroke marine engines, which is not dealt with in this article and which is the subject of additional articles. “Heavy 2-stroke engine – Areas of application and specific structural characteristics” [BM 2 653] and “Heavy 2-stroke engine – Specific characteristics of auxiliary systems” [BM 2 654].
The reader will find a glossary and a table of acronyms used at the end of the article.