DKW (Dampf-Kraft-Wagen) was a German automobile and motorcycle manufacture. DKW was one of the early adopters and innovators in the development of small two cycle engines. In 1919 Hugo Ruppe constructed a 18cc .25hp two cycle toy stationary engine which went into production. In 1920/21 DWK starts producing auxiliary bicycle engines based on Ruppe's improved 1hp version of the engine. In 1921 10,000 auxiliary bicycle engines are sold. In 1922 DKW produced 2,000 of its first motorcycles as well as 20,000 auxiliary motors with production rising each year. The development of DKW's Schnuerle Loop_Scavenging in 1927 brings a huge advance to two stroke engine technology. By 1928 DKW was the largest motorcycle factory in the world.