A ceramic engine is a theoretical engine made from technical ceramic material (engineered ceramics made to withstand extreme environments). The engine was a proof-of-concept popularized by successful studies in the early 1980s and 1990s. Under controlled laboratory conditions, ceramic engines outperformed metallic engines in terms of weight, efficiency, and performance. The plan for an all-ceramic engine was seen as the next advancement in future engine technology. However, ceramic engines have not entered the automobile market because of manufacturing and economic problems.