More MBS CoverageTRAVERSE CITY, MI – Most of Ward’s editorial staff this year blew into town for the Management Briefing Seminars on a torque tsunami generated by diesel-powered test cars from Robert Bosch GmbH.

The vehicles include a Honda Accord, BMW 535 and Audi A6.

Bosch maintains an impressive armada of European-spec diesel-powered vehicles to showcase to diesel-deprived Americans. The company’s fuel-injection and engine-management contributions to the spectacular new generation of diesels is largely unavailable in the U.S.

Diesel technology continues to accelerate as quickly as the vehicles motivated by these new high-tech powerhouses, and the vehicles Bosch currently is demonstrating erase any doubt diesel is capable of winning the hearts and minds – not to mention the wallets – of U.S. customers.

Bosch’s European version of the Honda Accord is powered by the first diesel developed in-house by Honda Motor Co. Ltd., which to now has fastidiously avoided compression ignition.

The 2.2L i-CTDi 4-cyl. makes a modest 140 hp but pounds out 251 lb.-ft. (340 Nm) of torque, which rivals some of the best V-6s.

Our test car, with a manual transmission, is rated on the European drive cycle to deliver 33 mpg (7.1L/100 km) in the city and 52 mpg (4.5L/100 km) on the highway, figures that respectively are 79% and 53% stingier than the same car with a gasoline 2.4L DOHC 4-cyl.

We can’t gauge the city figure, but a 300-mile (483-km) trip to Traverse, done almost entirely at an indicated 78 mph (130 km/h) on cruise control, netted a disappointing but still thrifty 30.7 mpg (7.7L/100 km) – a far cry from the Euro-rated 52 mpg.

Honda Accord, Audi A6, BMW X3 and 535 sedan are European-spec diesels.

We attribute some of the bothersome discrepancy to the high average speed, quality of the available diesel fuel and the fact we couldn’t resist unleashing the i-CTDi-powered Accord for several extended 110-mph (177-km/h) cruises, which highlight Honda’s chief design goal: making this engine’s combustion process transparent.

The Accord diesel is almost unidentifiable as such. With the i-CTDi idling, one can lift the hood, and the most prevalent noise impression is that of slightly louder ancillaries. The impression of “clatter” simply isn’t there.

When starting up and pulling away from a stop, there is a momentary grouchy vibration, then everything settles to gasoline engine-like noise, vibration and harshness refinement. At our preferred cruising speed, wind and road noise totally eclipse any sound emitted from Honda’s first-ever diesel. Drop a hand on the shift lever at 100 mph (161 km/h), and you may expect buzz. Forget it – the shifter is as immobile as the Sphinx.

Honda’s diesel target was refinement. BMW AG’s ambition for its scorching new sequentially turbocharged 3L inline 6-cyl. powerplant was a diesel that befits the “Ultimate Driving Machine.” That means ultimate refinement and ultimate performance.

The technology-packed BMW turbodiesel doesn’t cede a horsepower number that’s weaker than a like-sized gasoline engine, which is typical even for today’s most advanced diesels.

No, the new BMW I-6 diesel makes a preposterous 272 hp, 17 hp better than its all-new gasoline engine of the same layout and size. And the sequentially turbocharged BMW diesel’s 412 lb.-ft. (560 Nm) of torque is more than that developed by the thundering 5L DOHC V-10 in the M5.

Editor Drew Winter reports interstellar velocities are always within reach of the 535d, as is the ability to lay rubber (through the 6-speed automatic) at will.

BMW’s hottest diesel does this while also providing about 28 mpg (8.4L/100 km) at 80-85 mph (129-137 km/h) cruising speeds.

Bosch also loaned out an Audi A6 with the auto maker’s latest 3L V-6 turbodiesel, which produces 221 hp and 332 lb.-ft. (450 Nm) of torque.

For the trip up, we achieved better than 33 mpg (7.1L/100 km) in the A6 through stop-and-go construction and wide-open driving, while reveling in the gobs of low-end torque. Noise was not a factor, at any speed, neither was smell.

We also are driving, courtesy of Bosch, BMW’s “old” 3L turbodiesel I-6 in the X3 cross/utility vehicle. It produces 204 hp and 302 lb.-ft. (410 Nm) of torque.

In the X3, the 3L may be old, but it is wholly capable. Turbo lag is minimal, and at a standstill an occupant outside the vehicle would strain to identify the powerplant as a diesel. The engine injects a healthy dose of excitement and efficiency in this reasonably priced CUV.

Performance like this obviously can sell, and the new-tech diesels also can readily change the old perceptions of diesel as ill-refined – and perhaps worse, slow.

But if that’s not enough, diesel’s “green” future is growing appreciably brighter.

First, the nation’s newly passed energy legislation includes new tax incentives for individuals who buy diesel-powered vehicles.

The incentives are the same as those given to purchasers of hybrid-electric vehicles (HEVs), which to now have enjoyed a high profile as an option to reducing energy dependence. (See related story: Clean Diesels to Get Tax Break)

And next June begins the nationwide phase-in of ultra-low sulfur diesel fuel. The lack of high-quality fuel has restricted the attractiveness of diesels in North America because excess sulfur ruins the catalytic technology diesels need to comply with the stringent new clean-air provisions of California’s LEV II and federal Tier II emissions standards.

The low-sulfur fuel will, in essence, make it possible to sell emissions-compliant diesels nationwide.

bvisnic@primediabusiness.com