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Turbocharged direct injection or TDI is a design of turbodiesel engines featuring turbocharging and cylinder-direct fuel injection〔 that was developed and produced by the Volkswagen Group (VW AG). These TDI engines are widely used in all mainstream Volkswagen Group marques of passenger cars and light commercial vehicles made by the company〔(【引用サイトリンク】title=TB 20 addendum – Technical Bulletin for Volkswagen Group timing belt renewal intervals )〕 (particularly those sold in Europe). They are also used as marine engines in Volkswagen Marine and Volkswagen Industrial Motor applications. Some TDI engines installed in 2009 to 2015 model year Volkswagen Group cars sold through 18 September 2015 had an emissions defeat device,〔〔 which activated emissions controls only during emissions testing. The emissions controls were suppressed otherwise, allowing the TDI engines to exceed legal limits on emissions.〔 VW has admitted to using the illegal device in its TDI diesel cars.〔 In many countries, TDI is a registered trademark of Volkswagen AG.〔 The TDI designation has also been used on vehicles powered by Land Rover-designed diesel engines. These are unrelated to Volkswagen Group engines. ==Overview== The TDI engine uses direct injection,〔〔 where a fuel injector sprays atomised fuel directly into the main combustion chamber of each cylinder,〔〔 rather than the pre-combustion chamber prevalent in older diesels which used indirect injection. The engine also uses forced induction by way of a turbocharger〔〔 to increase the amount of air which is able to enter the engine cylinders,〔 and most TDI engines also feature an intercooler to lower the temperature (and therefore increase the density) of the 'charged', or compressed air from the turbo, thereby increasing the amount of fuel that can be injected and combusted.〔 These, in combination, allow for greater engine efficiency, and therefore greater power outputs〔 (from a more complete combustion process compared to indirect injection), while also decreasing emissions and providing more torque〔 than the non-turbo and non-direct injection petrol engined counterpart from VAG. Similar technology has been used by other automotive companies, but "TDI" specifically refers to these Volkswagen Group engines. Naturally aspirated direct-injection diesel engines (those without a turbocharger) made by Volkswagen Group use the Suction Diesel Injection (SDI) label. Because these engines are relatively low displacement and quite compact, they have a low surface area. The resulting reduced surface area of the direct injection diesel engine reduces heat losses, and thereby increases engine efficiency, at the expense of slightly increased combustion noise. A direct injection engine is also easier to start when cold,〔(【引用サイトリンク】url=http://www.volkspage.net/technik/ssp/ssp/SSP_316.pdf )〕 because of more efficient placing and usage of glowplugs. Direct injection turbodiesel engines are frequent winners of various prizes in the International Engine of the Year Awards. In 1999 in particular, six out of twelve categories were won by direct injection engines: three were Volkswagen, two were BMW, and one Audi. Notably that year, the Volkswagen Group 1.2 TDI 3L beat the Toyota Prius to win "Best Fuel Economy" in its class. The TDI engine has won "Green Car of the Year" award in the years 2009 (Volkswagen Jetta 2.0 litre common-rail TDI clean diesel) and 2010 (Audi A3 TDI clean diesel) beating other various electric cars. Both those cars were designed to cheat during testing conditions. 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「Turbocharged direct injection」の詳細全文を読む スポンサード リンク
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