As carmakers work to meet stricter global emissions standards, engine downsizing has become an important strategy for increasing efficiency. That's why more four-cylinder engines are turning up in luxury cars. However, while modern four-cylinders can often match the power of larger engines (usually with turbocharging), they often aren't as refined as the larger six- and eight-cylinder engines most luxury car buyers are used to.
To solve that problem, Audi is reportedly looking to a clean-sheet design for future four-bangers. According to Autocar, the German company is planning a four-cylinder engine that will run as smoothly as a six- or eight-cylinder. The engine would use a non-conventional layout to avoid generating the internal forces that make normal four-cylinders un-smooth.
Audi was awarded a patent for an "internal-combustion engine with multi-joint crank drive and additional masses on articulated connecting rods for damping free inertia forces." Essentially, the pistons and connecting rods would be offset from the crankshaft, helping to dampen vibration.
In this design, the rods would be connected to the crankshaft with a secondary set of rods, which would have counterweights to further damp internal forces. So instead of one connecting rod running between the crankshaft and piston, as in most internal-combustion engines, there will be two.
That arrangement reportedly won't affect packaging too much. The new engine would be about as wide as a typical V engine. Audi hasn't confirmed the engine for production, but it would fit into a larger strategy for increased efficiency that also includes a plethora of plug-in hybrid models and electric turbocharging as well.