BMW
After the end of World War I in 1918, BMW was forced to cease aircraft engine production by the terms of the Versailles Armistice Treaty. To remain in business, BMW produced farm equipment, household items and railway brakes. In 1922, former major shareholder Camillo Castiglioni purchased the rights to the name BMW, which led to the company descended from Rapp Motorenwerke being renamed Süddeutsche Bremse AG (known today as Knorr-Bremse). Castiglioni was also an investor in another aircraft company, called "Bayerische Flugzeugwerke", which he renamed BMW.The disused factory of Bayerische Flugzeugwerke was re-opened to produce engines for buses, trucks, farm equipment and pumps, under the brand name BMW. BMW's corporate history considers the founding date of Bayerische Flugzeugwerke (7 March 1916) to be the birth of the company.
Straight-six engine
After becoming famous in the last year of World War I through their production of the liquid-cooled BMW IIIa aviation engine of straight-six layout — itself a massive gasoline-fueled engine of some 19 litres (1,164 cu. in.) displacement, BMW introduced its first straight 6-cylinder automotive engine in 1933: the Fritz Fiedler-designed, 30 hp, 50 lb-ft, M78. BMW developed straight-six engines for the post-World War II era by adding two cylinders to its M10 four-cylinder design. In 1968, it introduced a M30 straight-six design with the same 30° slant, overhead camshaft layout, and 100 mm bore spacing as the four. It originally intended to follow up with a V8 engine line in the early 1970s, but when the 1973 oil crisis hit, BMW canceled its V8 plans and concentrated on refining and enlarging its straight-six lineup. These included a smaller straight-six in displacements (the BMW M20), versions of the larger BMW M30 up to (the S38B38); and beginning in 1983, a series of M21 straight-six diesel engines. In 1986, BMW introduced the M70 V12 which was essentially two straight-sixes on the same crankshaft. In the mid-90s, they produced a series of straight-6s based on the M50 architecture, the ultimate of which was the 330-360 hp S54, used up to 2008. BMW offered a straight-six for their following line up BMW 1 Series, BMW 3 Series, BMW 4 Series, BMW 5 Series, BMW 6 Series, BMW 7 Series, BMW X1, BMW X3, BMW X5, BMW X6, the retired Z3, and current BMW Z4. The BMW B58 3-liter turbocharged inline 6-cylinder, (installed in the M240i) topped Ward's 10 Best Engines of 2017 list. The B58 is rated at 335 horsepower and 369 lb-ft of torque, while achieving 26 mpg.