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Atlas is a name for a family of modern inline piston engines for trucks from General Motors. The series debuted in 2002 with the Oldsmobile Bravada, and is also used in the Chevrolet TrailBlazer and Colorado and their GMC twins, the Envoy, Canyon and ((SAAB 9-7X)) in production, the engines use GM's Vortec name, and I4, I5, and I6 engines are all part of the same family, sharing the same manufacturing equipment, rods, pistons, valves, and other parts. They feature variable valve timing on the exhaust side, electronic throttle control, and a special oil pan with a pass-through for the half shafts in four-wheel drive vehicles. The inclusion of VVT on the exhaust camshaft side allows the Atlas series to meet emissions standards without the use of EGR, simplifying the engine design and increasing power for a broad power curve. The LL8 shares 75% of its components with the LK5 and L52; while the LK5 and L52 share 89% of their components. The Atlas program began in 1995 along with the planning for GM's next-generation mid-size SUVs and pickup trucks. These vehicles were designed around the I6 engine. The I6 version was used in a Baja 2000 racing truck, winning its first race in a class that also included V8 engines. Another I6-powered truck won the truck class at the Pikes Peak International Hillclimb. The I6 Atlas engines were produced at the Flint Engine South plant in Flint, Michigan, while the I4 and I5 versions were produced at the Tonawanda Engine plant in Tonawanda, New York, near Buffalo. == LL8 == The LL8 (or Vortec 4200), is a straight-6 truck engine. It was the first Atlas engine, and was introduced in 2002 for the Chevrolet TrailBlazer, GMC Envoy, and Oldsmobile Bravada, the engine is also in use in the Buick Rainier, Saab 9-7, and the Isuzu Ascender. It displaces ,〔()〕 with a bore and stroke. It has four valves per cylinder, utilizes dual-overhead cams DOHC design, and features variable valve timing on the exhaust cam, a first for GM Inline engines. When introduced, this engine's power was at 6000 rpm and torque was at 3600 rpm. 2003 saw a slight bump in power to , while torque was unchanged. For 2006, power was increased to at 6000 rpm and torque to ) at 4800 rpm with the addition of a MAF and a complete internal redesign of the engine; however due to the new SAE rating procedures ratings can vary slightly between years. Engine redline is 6300 rpm. The LL8 was on the Ward's 10 Best Engines list for 2002 through 2005 and was the basis for all the other Atlas engines. With the closing of the Moraine, Ohio plant and the termination of the GMT360 platform (Chevrolet TrailBlazer, GMC Envoy, etc.) the production of the LL8 was also terminated. Applications: * 2002–2009 GMC Envoy, ''Envoy XL'', and ''Envoy XUV'' * 2002–2009 Chevrolet TrailBlazer and ''TrailBlazer EXT'' * 2002–2004 Oldsmobile Bravada * 2004–2007 Buick Rainier * 2003–2008 Isuzu Ascender * 2005–2009 Saab 9-7X 4.2i 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「General Motors Atlas engine」の詳細全文を読む スポンサード リンク
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