Complex sentence: Between 1915 and 1916 their only car was a 10/12hp model, then between 1919 and 1921, the Type 10 was equipped with a 4-cylinder 1,592cc side valve engine.
Split into simpler sentences: Between 1915 and 1916 the only car was a 10/12hp model. Between 1919 and 1921 the Type 10 was equipped with a 4-cylinder 1,592cc side valve engine.