Launched in 1968, the Jaguar XJ was a luxury sedan sold under the British Jaguar luxury marque. Since then It have had served as the Jaguar flagship model for most of its production span which continues till today. The original model, the last Jaguar saloon was designed by Sir William Lyons, the company's founder. The "XJ" designation was originated from the car's code name during development, standing for Experimental Jaguar. The XJ6, using 2.8 L (2790 cc/170 in³) and 4.2 L (4235 cc/258 in³) straight-six cylinder versions of Jaguar's renowned XK engine, replaced most of Jaguar's saloons – which, in the 1960s, had expanded to four separate ranges.