<http://schema.org/articleBody>
"           New Technology Promises Even Better Torque   Diesel efficiency has attracted lots of automakers \u2014 and almost half of European new-car buyers. High-pressure common-rail direct injection is all the rage. (See last month&amp;#039;s First Drive of the high-performance Mercedes-Benz E320 CDI; see also &amp;quot;,&amp;quot; May 2003.)   What&amp;#039;s more, there is new technology that promises to enhance a diesel&amp;#039;s strong point, namely its abundant torque. Our European Editor Paul Fr\u00E8re learned details at this year&amp;#039;s Geneva show. His report follows:   Both and Opel have exhibited 2-stage turbocharged diesel engines, a 3.0-liter inline-6 from BMW, a 2.0-liter inline-4 from Opel. Although the Opel is still a prototype, the BMW has already powered a special X5 finishing 3rd overall in this year&amp;#039;s Dakar Rally.   With both, the aim is to get high torque as soon as possible, reducing turbo lag to an absolute minimum. In overview, each uses a small turbocharger generating boost at low crankshaft speed and a larger one taking over as engine revs rise.   At low rpm, a closed flap valve directs all exhaust gases to the small turbo&amp;#039;s turbine, thus quickly generating useful boost on demand. From the small turbo, these exhaust gases are fed to the turbine of the large turbo, where their residual energy prepares the latter for its boost regime.   As engine rpm increases, and the small turbo becomes saturated, the flap valve gradually opens \u2014 thus routing increasingly more exhaust directly to the large turbo. This turbo pressurizes the intake air before it reaches the small turbo, thus enhancing the latter&amp;#039;s effect.   As engine speed approaches 3000 rpm, the flap opens completely, giving the large turbo full benefit of the exhaust gases. Simultaneously, a check valve in the intake system opens to allow a bypass of the small turbo (which continues to spin up as exhaust backpressure increases). An important feature is a perfectly smooth transition from small- to large-turbo operation.   BMW sets a maximum boost of 2.85 bar absolute (26.6 psi gauge). Its 3.0-liter engine produces 268 bhp (thus, almost 90 bhp/liter, quite an achievement for a diesel) with maximum torque of 413 lb.-ft.   Opel&amp;#039;s, though not yet a production engine, runs at even higher boost, 3.2 bar absolute (31.7 psi gauge). It produces 209 bhp from its 2.0 liters (thus, more than the magic 100 bhp/liter) and 295 lb.-ft. of torque.   Both powerplants meet next year&amp;#039;s Euro 4 emissions regulations as well.   My BMW diesel   The good folks of Robert Bosch Corp. U.S.A. were kind enough to lend me a BMW 530d for my visit to Detroit&amp;#039;s SAE 2004 World Congress. It was early March, so I had opportunity to experience a state-of-the-art diesel in rather less balmy clime than Southern California&amp;#039;s.   Reasonably frigid conditions \u2014 well, it was in the low 20s \u2014 necessitated only a slight pre-heat pause between key twist and compression-ignition, somewhat less than a couple of seconds. During warmup, the sounds of the inline-6&amp;#039;s combustion were diesel-like, but not to excess, especially within the 5 Series&amp;#039; cabin. Once underway, up to temperature and cruising around, the 530d was difficult to distinguish from its gasoline-burning sibling.   Its prodigious torque, 369 lb.-ft. at a mere 2000 rpm, was one giveaway, oft employed in being the first across just about any intersection. Another was the car&amp;#039;s parsimonious use of fuel.   I enjoyed a total of 364 miles in my 530d, much of this mixing it up with suburban Detroit traffic. I must say, I didn&amp;#039;t see as many diesel stations as I encounter here at home. And the one I ultimately visited wasn&amp;#039;t all that spiffy; its diesel pump looking a bit grimy (from disuse?). In any case, 12.7 gal. filled the tank, which worked out to 28.7 mpg. To put this in perspective, our recent seven-car comparison included a gasoline BMW 530i that got 21.1 mpg.   Even with diesel priced comparably to gasoline, in Detroit as it is around here, there are significant savings to be had. What&amp;#039;s more, I&amp;#039;m looking forward to driving that 2-stage-turbodiesel BMW described by Paul Fr\u00E8re earlier in this column. The same 3.0 liters \u2014 and 413 lb.-ft. of torque? Where do I sign? "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.roadandtrack.com/new-cars/car-technology/news/a10098/a-vote-for-diesels/>