For years, we’ve reveled in the wealth of turbocharged engines coming from Nissan Motor Company; after all, it wrote quite a few of the chapters in the Big Book of Boost. From the early Datsun days, when force-fed Fairlady 280Z race cars were piloted by world famous actor and racing fanatic Paul Newman, to the inception of the complex 300ZX twin-turbo sports coupe, and the mighty Godzilla GT-R, Nissan has long been addicted to turbochargers.
History lesson aside, word on the street is that Nissan has been busy reinventing the modern turbocharged gasoline motor, and according to a report by Automotive News, the automaker’s design may “make some of today’s advanced diesel engines obsolete.” By utilizing something called variable compression technology, the brilliant minds over at Nissan have given a VC-T motor the ability to choose the optimal ratios for combustion capabilities at any given moment, negating a lot of the efficiency woes commonly associated with gas engines.
If this design works as intended, the VC-T engine will offer the performance of a typical turbocharged gasoline engine, and match that with the power and fuel economy of modern day diesels and hybrids — a level few gas engines can reach. So while Dieselgate plods on, and Jaguar installs extremely clever small diesel engines in its XE sports sedan line, a fresh alternative warrants serious consideration.
“Diesel engine is a hot topic globally. We believe this new engine of ours is an ultimate gasoline engine that could over time replace the (advanced) diesel engine of today,” says Kinichi Tanuma, a lead Nissan engineer who spearheaded product development for Infiniti. Tanuma’s statement nails down a lot of the nagging questions and concerns hybrid and diesel haters have these days, giving them hope for the future of the gas engine.
The groundbreaking turbo 2.0-liter is expected to be unveiled at next month’s Paris auto show, and according to sources will begin its world tour in an Infiniti model that has yet to be unveiled. While details are scarce on power gains and what maintenance will look like on something this small and advanced, the automaker has confirmed that the Nissan brand and its European alliance partner, Renault, will both use the VC-T powerplant in future products.
Details are also murky on how many different vehicles will receive the scrolling 2.0-liter VC-T motor, but we have some evidence of where it will end up. Fuel economy averages are 27% better than the 3.5-liter V6 engine it’s replacing, and since it reportedly offers the same amount of horsepower while matching the torque curve of a diesel engine, it could end up making an appearance across the Nissan lineup.
In the past, automotive engineers had to select a gasoline engine’s compression ratio to either focus on power or economy, with a lower ratio reserved for many turbocharged options. Simply explained, combustion compression ratios and piston sizes regulate how much of the air-fuel mixture gets compressed within an engine’s cylinders prior to being ignited. Depending on the kind of engine you have, and how many pistons are in use, higher ratios typically yield greater efficiency, while low compression, turbocharged setups give the grunt to get your ass off the line in a hurry, but at the expense of fuel economy.
Nissan claims that its VC-T prototype is cheaper than many of today’s complex turbo powerplants, and that it should also meet emissions regulations in most international markets without the need for costly diesel treatment systems. Engineers say that the powertrain can choose compression ratios anywhere between 8:1 and 14:1, which covers almost the entire gamut of modern day gasoline production engines. Average vehicles typically rock compression ratios ranging between 8:1 to 10:1, which the VC-T motor likes to own outright before jumping into exotic sports car territory, which can run on 12:1 ratios or more.
“We think the VC-T engine could replace or become an alternative to some of today’s advanced diesel engines,” Tanuma concludes. While that’s interesting enough, let’s not rule out the fact that the engine’s efficiency and powerband could be further enhanced by the addition of an electric hybrid system — an option Nissan admits could be in the cards down the line.