Ecotec Small and Flüsterdiesel
Don’t let the new Chevrolet Cruze’s gas engine displacement mislead you into thinking it’s a refresh. This is a completely new engine capitalizing on GM’s latest combustion-optimization expertise. Similarly, the new 1.6-liter diesel — designed in Europe where they really “get” oil-burners — is claimed to be the world’s quietest diesel. Already in production in a brace of Opels (Astra, Meriva, Mokka, and Zafira), this characteristic has inspired the European press to dub it the Flüsterdiesel, or “whisperdiesel.”
Let’s look at the gasser first. Already powering the Chinese Cruze (which is a half-generation off of ours) and destined for the Opel Astra, as well, you can basically think of this 1.4-liter, turbocharged inline-four as an Opel Adam 1.0T with an extra cylinder. We’ve driven and been impressed with that little triple, and this four-banger shares a long list of parts and dimensions with it: bore (74.0mm), stroke (81.3mm), cylinder-bore spacing, pistons with low-friction rings, connecting rods, cam drive, centrally located direct fuel injectors, piston-cooling oil squirters, sensors, and even engine control systems. Both integrate the exhaust manifold into the cylinder head, both employ an extremely rigid aluminum block, a bedplate lower-end structural design, and a forged steel crankshaft, and they both use stamped-steel oil pans.
These last few qualities contribute considerably to reducing the noise emanating from the engine, and indeed Chevrolet claims this Ecotec four is 50 percent quieter than VW/Audi’s competing 1.4-liter turbo. Boost from the MHI turbo peaks at 14 psi — impressive in an engine running 10.0:1 compression on regular unleaded fuel. Engine output increases from 138 hp and 125 lb-ft to an SAE-certified 153 hp and 177 lb-ft. (Those numbers inch up a bit if you run premium.) Auto stop/start technology will be included on models with the 6T35 automatic transmission. (An M32 six-speed manual is standard.)
GM estimates the highway fuel economy figure will start with a 4, even without extra-cost Eco trimmings. And between the economies of scale realized on an engine architecture that will be produced in quantities of 2.5 million per year (ours will come from Flint, Michigan, and Toluca, Mexico) and savings from not certifying a third engine, this greatly improved engine can now serve as the base Cruze powertrain without resulting in a commensurate price increase.
The gasoline engine will be followed “closely” by the 1.6-liter “whisperdiesel.” Tech highlights include aluminum block and head construction with a rigid bedplate design, variable-output oil pump, and ceramic glow plugs. No official output figures have been released yet, but in the European applications it makes 134 hp and 236 lb-ft. That’s down from the current 2.0-liter’s 151 hp and 264 lb-ft, but the engine is considerably lighter, and so is the car, so performance should be similar with fuel economy meeting or exceeding the current 27/46 mpg EPA city/highway.
GM claims that engine-out emissions are among the lowest in the class. Nevertheless, federalizing the Euro-spec “1.6 CDTi” engine requires increasing the precious metal content of the oxidation catalyst and using a selective catalytic reduction emissions system. Other changes to the U.S.-spec engine include basic engine calibration, diagnostics, and testing and development for our wider range of climate conditions. The new engine will also be compatible with B20 biodiesel fuel.
So how does it come by that Flüsterdiesel moniker? Mostly by attacking noise at the source. Carefully timing the multiple fuel-injection events manages the rise in cylinder pressures to quell some of the racket, and isolating the fuel-injection rail and injectors eliminates much of their noise. The sophisticated design of the ribbing and wall-thickness sections of the aluminum block reduces radiated noise, and moving the cam drive to the rear of the engine means that the transmission serves as a natural insulator to most of that chain noise. There’s also a full foam insulation package on top of the engine. We’re told it can be difficult to tell if the engine is running, let alone if it’s a diesel.
Even marketing it as a premium engine, Chevrolet is setting an aggressive sales target of besting the VW Jetta TDI’s 37,000 per year, and if the reality approaches the hype, that might just be achievable.