Automakers Ditch Downsizing After Finding Small Engines Pollute More

Engine / 35 Comments

Yes, you read that right. Is it Christmas already?

Automakers and government regulators have recently been taking us for a gut-wrenching ride when it comes to engine sizes. In attempts to meet stringent standards, engines have been losing cylinders and size and gaining turbochargers to become more efficient. The problem is, downsizing doesn't always make a car more environmentally friendly. According to Reuters, it can actually make an engine spew more toxic gases, so automakers are going back to larger displacements.

If it sounds like a mind boggle then you're not alone. Essentially, the problem is that automakers have reached the limit of what engines can do. Slicing away engine real estate by the cubic inch and replacing it with forced induction might cut down on NOx emissions during lab testing, but the artificially light loads and fair temperatures are tough to mimic in real life. Unfortunately for those of us wishing for our V8 BMW M4, this won't happen. First off, the problem is mainly plaguing European cars that have engines under 1.0-liters in size and a bit larger, so yes, as long as a turbocharged 6-cylinder is more efficient than a V8, the downsizing trend will continue there. The problem is that these smaller engines are more strained.


The additional heat from the exertion can cause small turbo engines to spew up to 15 times more NOx emissions than during testing. Gas engines aren't much better. Some, like Renault's 0.9-liter unit, spray extra fuel into the engine to prevent overheating, which reduces fuel efficiency and emits more hydrocarbons, fine particles, and carbon monoxide. To meet upcoming European emissions standards, automakers like GM, Volkswagen, and Renault are going to upsize some of their smallest engines to prevent this problem. Unfortunately for cars like the M4, there will come a time when the only way to maintain power with new strict standards is to make them hybrid or electric. Sorry, we know this isn't the good news you thought it would be.

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