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EuroWire – March 2012
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Transatlantic cable
E ciently powerful 4-cylinders. An example of what is
rapidly becoming the de facto con guration for small
gasoline engines was found in the engine bay of the
Cadillac ATS sedan: a 2-litre 4-cylinder engine incorporating
twin-scroll turbocharging, direct fuel injection, a relatively
high compression ratio, and low-friction internal parts.
The engine layout of Cadillac’s rst 4-cylinder in more than
20 years is similar to that in certain Mazda, Ford and Honda
models;
Divide and conquer. Typical of the latest turbocharged
engines, the 201-horsepower 4-cylinder of the Hyundai
Veloster Turbo is equipped with a twin-scroll turbocharger.
By splitting the ow of exhaust gases between two
passageways, twin-scroll turbos isolate cylinders whose
exhaust pulses interfere. This makes for a more responsive
engine by reducing the delay in building up pressure;
Direct delivery. Hyundai says that its use of direct fuel
injection, variable valve timing, and variable intake tuning
in the Genesis Coupe’s 3.8-litre V-6 produces net gains of
42 horsepower and 29 pound-feet of torque. Peak
horsepower is 348; torque tops out at 295 pound-feet. Direct
fuel injection sprays fuel into the engine’s cylinders rather
than into the passageways farther upstream, improving the
precision of delivery and providing some cooling e ect;
Doing without a throttle. The new Dodge Dart uses Fiat’s
MultiAir 2 valve-throttling system in two of its 4-cylinder
engines (one of them from Fiat). Like the Valvetronic system
that BMW pioneered ten years ago, MultiAir 2 uses the
engine’s valves rather than a throttle plate to control air
coming into the cylinder under certain conditions. Power
losses resulting from the engine having to pull air past the
throttle is reduced, engine e ciency enhanced;
Double clutching. Another bene t to Chrysler of
Fiat’s ownership comes in the form of Fiat Powertrain
Technologies’ dual-clutch 6-speed transmission. Volkswagen
pioneered dual-clutch transmissions in production cars
nearly a decade ago, but only recently have they become
common. Mr Stenquist wrote: “This technology o ers
automatic shifting but provides better e ciency than
conventional automatics because it assures a no-slip
mechanical coupling of the engine to the gearbox rather
than a uid coupling.”
Steel
However spectacular, the cars were
not the whole show at Detroit
Materials – notably the lighter, pliable steel intended to outdo
rival products in meeting the demands of the automotive
industry – commanded much attention at the North American
International Auto Show. In what the
Wall Street Journal
termed a
‘third wave’ in automotive steel, American producers are bending
their e orts toward the development of advanced high-strength
steel, employing continuous-annealing methods to modify its
microstructure and thus its malleability and toughness. Success,
if they achieve it, will pay o handsomely. The domestic steel
industry’s biggest customers, US car makers were expected to
produce 13.4 million vehicles in 2011, up from 10.4 million in
2009. But the makers of aluminium, plastics and sponge are
in hot pursuit, pressing the claim that their products are more
malleable and lighter – key considerations for design and fuel
e ciency, respectively.