Rising gas prices may necessitate a renewed focus on fuel economy, particularly in larger cars.
The average gas price in the US is up around $3.00 per gallon for regular unleaded. Fuel economy is at a premium and automakers are trying to find new ways to make the internal combustion engine more efficient and more powerful. Koenigsegg has its “Freevalve” variable valve timing technology. Infiniti has a variable compression ratio engine, while many other companies use cylinder deactivation. However, Audi may have just come up with yet another way to extend the use of the internal combustion engine. Autoguide.com reports that the German automaker just submitted a patent for an engine that makes use of different-sized cylinders. This, in effect, would be like putting two different engines into the same block.
The patent indicates that the two sizes of cylinders can run independently of one another, or in conjunction. Whichever is more efficient in a given scenario. Audi was able to do this by designing the engine with a crankshaft decoupler. This means that the different sized pistons are not necessarily connected all the time. This conveniently removes the need for harmonic balancers. Unlike cylinder deactivation, the unused cylinders don’t need to keep moving, therefore reducing engine vibration.
Different-sized cylinders could lead to better fuel economy
Why use different sized cylinders? Well, think about it this way: A smaller engine uses less gas when coasting on the freeway, but has a harder time getting a vehicle up to speed. With this model, you can use the big cylinders for acceleration, then switch to the smaller ones when all you need to do is cruise.
There are certainly going to be some downsides. The first, and most obvious is the extra weight that a camshaft decoupler will incur. That, plus an asymmetrical engine block wills surely use some extra materials. We can also assume that this system will cause some extra maintenance items down the road, meaning more expense for the customer. Perhaps the fuel savings will be enough to compensate for the potential increased maintenance costs.
In other news, Audi just revealed the all-new Audi Q8 in China. This vehicle will make use of a mild hybrid system that could aid this crazy new engine concept in smooth operation. Of course, that depends on whether Audi will actually bring this engine to market in the future. To learn all about the new Q8, be sure to watch the video below:
UPDATE: Thanks to Autoguide.com for their original reporting on this story.