Published on April 1st, 2013 | by Daniel Sherman Fernandez0
BMW’s All New 3-Cylinder Engine Explained
BMW is striving for even better fuel economy with a new range of engines. This will be a new family of small engines derived from BMW’s world-famous inline six-cylinders.
This new 3-cylinder engine will appear roughly one year from now in the BMW i8 plug-in hybrid sports coupe. This car will play a big role in meeting global regulations. To be used in a variety of “BMW Group” products, which means not only BMWs, but also MINIs. This all new 3-cylinder can be mounted lengthwise or transversely.That means it can be used in the company’s first-ever front-wheel-drive platform for the next generation of MINI vehicles, as well as the lowest end of the BMW range.
BMW’s engine designers have always considered half a liter to be the ideal size for a combustion chamber, meaning that fours would be roughly 2.0 liters and sixes would be roughly 3.0 liters. Look at BMW’s lineup and you’ll see lots of engines and model that fall into that pattern. But with higher output from smaller displacements, could a 1.5-liter engine that was direct-injected, turbocharged, and fitted with variable valve timing actually produce the power of a low-end four–but with fuel efficiency up to 15 percent higher? BMW believes the answer is yes, and it offered up a pair of bright red test cars fitted with developmental test versions of the new 1.5-liter three-cylinder engine.
This new engine would have outputs from 120 to 200 horsepower, depending on how it was tuned. When used in the BMW i8 plug-in hybrid sports coupe, which will use the new 3-cylinder mounted transversely to power the rear wheels, while an electric motor powers the fronts. This layout is known as a “through-the-road hybrid,” and is used right now by only a few European car brands.
Another plus for the three-cylinder layout: Because its crankshaft throws are offset 270 degrees to accommodate firing pulses, and it has a balance shaft to counteract vertical vibrations, the new engine family comes closer to the smoothness of its inline 6 rather than the character of a 4-cylinder engine. This means, the BMW i8 will have acceleration comparable to that of today’s BMW M3.