Opel ADAM. Click to enlarge.

The first in a completely new family of small-displacement gasoline engines that will grow further over the next years, the 12-valve 1.0 ECOTEC Direct Injection Turbo is the next step in Opel’s powertrain offensive following the recent introduction of new 1.6-liter mid-size gasoline and diesel engine families (earlier post).

These three new powertrain families share a common DNA and development target: to be the most refined in their respective categories. Starting with a clean sheet of paper, Opel engineers in Rüsselsheim focused on eliminating ‘off-beat’ running characteristics which traditionally detract from the economical driving appeal of three-cylinder engines.

We not only set out to minimize fuel consumption and CO₂ emissions, we also wanted to demonstrate that three cylinders can be just as refined as four or more. We tackled at source the balance, noise and vibration issues typical of conventional three-cylinder engines, and we’re confident ADAM customers will be enthusiastic about the results.

—Dr. Matthias Alt, Opel’s Chief Engineer, Small Gasoline Engines

The cylinder block, in high pressure die-cast aluminum, is designed to reduce radiated and structure-borne engine noise, as well as reduce weight. The high-pressure fuel rail and injectors are also structurally isolated from the cylinder head to minimize the transmission of pulsing, while both the fuel pump and fuel line are acoustically treated.

A further contributor to running refinement is the installation of a balance shaft in the oil sump. Driven by a chain with inverted teeth for quiet running, it counter-rotates at crankshaft speed and is carefully mass-optimized to offset the inherent vibrations of a three cylinder operation.

Other noise attenuation measures include: acoustically-optimized covers for the top and front of the engine, the intake manifold and camshaft housings; crankshaft isolation with iron main bearing inserts; inverted teeth for camshaft drive chains; a low-hiss turbo charger, and a lower oil pan in steel.

The new 1.0 ECOTEC Direct Injection Turbo is quieter than many four-cylinder units. For example, in bench testing at full throttle, it emits lower noise levels across all engine speeds than similarly powerful gasoline naturally-aspirated engines of 1.6-liters displacement.

Mated to the six-speed gearbox, the new generation three-cylinder engine comes with Start/Stop functionality as standard. The 66 kW/90 hp version gives ADAM combined cycle fuel consumption as low as 4.3 liters per 100 kilometers (54.7 mpg US), with CO₂ emissions of 99 g/km (according to NEDC test procedure; preliminary data). Efficiency enablers include direct fuel injection, variable valve timing, weight-saving all-aluminum construction and a switchable water pump.

The 166 N·m of torque in the 1.0 ECOTEC Direct Injection Turbo is almost 30 percent more pulling power than the naturally-aspirated 1.6-liter generates at the same rpm. The 85 kW/115 hp version extends the torque plateau to up to 4,700 rpm.

The exhaust manifold is integrated within the aluminum cylinder head, to which the tiny, low-inertia, water-cooled turbocharger is directly bolted. This compact installation contributes to the delivery of a fast boost charge which gives the 1.0 turbo such strong, low-end power.

The six-vent fuel injectors in the direct injection system are centrally located above each piston to provide efficient combustion, and dual cam-phasing enables variable valve timing for optimum engine breathing. A twin displacement oil pump and a switchable water pump, which is disengaged when the engine coolant is cold in order to accelerate warm-up, also contribute to low fuel consumption.

With a compact design and a dry weight of only 37 kilograms, the new 6-speed gearbox is about 30% lighter than units it replaces.

Featuring a short lever travel and low shifting effort, the new transmission incorporates many of the smooth shifting refinements recently introduced by Opel. These include the use of gears with wide, asymmetrically-cut dog teeth and triple-cone synchronizers for first/second gear, with double cones for third/fourth. Reverse gear is also synchronized. In addition to ADAM, this new gearbox will be progressively introduced in other Opel models.

1.0 ECOTEC Direct Injection Turbo-powered Opel ADAM models will go on sale in late spring 2014 and their production will start in the summer. The new generation 1.0 ECOTEC Direct Injection Turbo with a new six-speed manual transmission joins ADAM’s current powertrain line-up of naturally-aspirated, four-cylinder units combined with 5-speed manual gearboxes: the 1.2-liter with 51 kW/70 hp and 115 N·m, and the two 1.4-liter units offering 64 kW/87 hp and 74 kW/100 hp, both with 130 N·m of torque.