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The Detroit Diesel Series 71 is a two-stroke diesel engine series, available in both inline and V configurations, with the inline models including one, two, three, four and six cylinders, and the V-types including six, eight, 12, 16 and 24 cylinders. The two largest V units used multiple cylinder heads per bank to keep the head size and weight to manageable proportions, the V-16 using four heads from the four-cylinder inline model and the V-24 using four heads from the inline six-cylinder model. This feature also assisted in keeping down the overall cost of these large engines by maintaining parts commonality with the smaller models. The inline six-cylinder 71 series engine was introduced as the initial flagship product of the Detroit Diesel Engine Division of General Motors in 1938. The V-type first appeared in 1957. The 71 in the model series designation refers to the displacement per cylinder in cubic inches (actually 70.93 cu in / ). Bore and stroke is the same to all units, at 4.25 x 5.0 inches (107.95 x 127 mm). All Series 71 engines use uniflow scavenging, where a gear-driven Roots type blower mounted to the exterior of the engine provides intake air through cored passages in the engine block and ports in the cylinder walls at slightly greater than atmospheric pressure. The engine exhausts through pushrod-operated poppet valves in the cylinder head(s), with either two or four valves per cylinder. Unit injection is employed, one injector per cylinder, with no high fuel pressure outside of the injector body. The injectors are cycled from the same camshaft responsible for opening the exhaust valves. As a two-stroke diesel engine that does not use crankcase aspiration cannot naturally aspirate (draw in) intake air, a blower is necessary to provide sufficient air to scavenge exhaust gasses from the cylinders and to supply air for combustion. Later high-performance versions were available with turbochargers, and turbochargers with intercooling, the turbochargers discharging into the Roots blower intake. The 71 Series went off of the market in the summer of 1995, and the Four Stroke Detroit Diesel Engine was introduced as a replacement. == Variants == The most popular incarnations of the series 71 engine as used for highway vehicle applications included the inline 6-71, the V-block 6V-71 (both widely used in transit buses) and the 8V-71. In addition to motorcoach propulsion, both inline and V types have found extensive usage in trucks, fire apparatus, motor homes, construction and industrial machinery, a few farm tractors, and military vehicles and equipment. The 71 series is very popular in marine applications, not only as a propulsion engine in small craft (Gray Marine 6-71) but as auxiliary power to drive generators, winches and other heavy shipboard machinery. The inline 6-71 engine, in all of its variations, was also available as a 'pancake engine' (here variably called either 6L-71 or 6N-71) for horizontal (underfloor) mount applications, such as on larger Crown and Gillig school buses and articulated puller transit buses (such as the Crown-Ikarus 286). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Detroit Diesel Series 71」の詳細全文を読む スポンサード リンク
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