Detroit Diesel

Detroit Diesel Corporation (DDC) is an American diesel engine manufacturer headquartered in Detroit, Michigan, United States. It is a subsidiary of Daimler Trucks North America, which is itself a wholly owned subsidiary of the German Daimler AG. The company manufactures heavy-duty engines and chassis components for the on-highway and vocational commercial truck markets. Detroit Diesel has built more than 5 million engines since 1938, more than 1 million of which are still in operation worldwide. Detroit Diesel's product line includes engines, axles, transmissions, and a Virtual Technician service.
Detroit engines, transmissions, and axles are used in several models of truck manufactured by Daimler Trucks North America.
Divisions.
Detroit Diesel consists of manufacturing operations of diesel engines for on-highway only, which is owned by Daimler AG. The former off-highway division was sold to MTU Friedrichshafen in 2006 and subsequently purchased by Rolls-Royce in 2014.
Clean Air Act violation.
In 1998, the EPA announced fines totaling $83.4 million against Detroit Diesel and six other diesel engine manufacturers, the largest fine to date, which evaded testing by shutting down emissions controls during highway driving while appearing to comply with lab testing. The manufacturers also agreed to spend more than $1 billion to correct the problem. The trucks used engine ECU software to engage pollution controls during the 20-minute lab tests to verify compliance with the Clean Air Act, but then disable the emissions controls during normal highway cruising, emitting up to three times the maximum allowed NOx pollution.
In 2016, Detroit Diesel agreed to pay US$28.5 million to resolve violations of US federal Clean Air Act. The company sold 7,786 heavy-duty diesel engines, which were assembled approximately 80% complete in 2009, including the crankshaft, block, pistons, and connecting rods, the short block engines were stored temporarily and completed the remaining assembly in early 2010 for use in trucks and buses of in model year 2010. These engines were alleged not to comply with stricter 2010 emission standards.
See also.
Stewart & Stevenson