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Infiniti's variable compression engine in the 2019 QX50 is the first of its kind

The world's first variable compression ratio engine is here, in a production car. That car is the 2019 Infiniti QX50, debuting this week at the Los Angeles Auto Show. The midsize crossover has seen a refresh that has brought it an all-new platform together with new driver assist features, but it's the engine that's the centerpiece here. Nearly everything is continuously variable under the hood of the QX50 – not only the new shift-by-wire XTRONIC CVT. The new VC-Turbo gasoline engine is able to change its compression ratio from 8:1 to 14:1, or anything in between depending of the driving situation; whether there is need for top-end power or turbodiesel-like torque from low revs, or optimized fuel economy. The pistons' reach is continuously adjusted by an electric "Harmonic Drive" motor, which controls a multi-link system, affecting the top-dead-center of the pistons and changing the compression. The engine can also switch between efficiency-maximizing Atkinson cycle and regular combustion cycle, on the go – and there's both multipoint injection and gasoline direct injection employed. The result is 268 horsepower at 5,600 rpm and 280 pound-feet of torque at 4,400 rpm; good figures for a 2.0-liter four-cylinder gasoline engine with a single-scroll turbocharger. Infiniti says that the FWD version's fuel economy of 27 miles per gallon combined is 35-percent better than the previous-generation V6 engine; in AWD guise, it reaches 26 mpg, which is a 30-percent improvement. The new engine is pretty much all-aluminum, but the vaguely magical-sounding "transformative multi-link components" behind the variable compression system are made from high-carbon steel alloy. The engine's multi-link system also enables it to do away with any balancing shafts, and Infiniti compares its smoothness to a V6 rather than a regular four-cylinder. In addition to the aforementioned tech, the VC-Turbo engine has the world's first active engine mount vibration damping system to smoothen its operation even further. Related Video:

Infiniti boss De Nysschen confirms next-gen Q60 Coupe, ponders high-performance variants

We've known since mid-December that Infiniti's new global model naming convention would turn the current-generation G37 Coupe into the Q60 Coupe starting next year, but we haven't been clear on whether the model-range-formerly-known-as-G would get a successor, especially as its volume has traditionally been a lot lower than its sedan counterpart.
Thankfully, Infiniti president Johann De Nysschen (above) has stepped up to confirm that the newly revealed Q50 sedan will receive a two-door counterpart, though perhaps not as quickly as some would like. According to an interview with Australia's CarAdvice.com, De Nysschen says "the coupe we can probably expect two-and-a-half to three years down the road." That news also suggests that if there's an eventual convertible version, that it's a long way off, too. Why so long? Infiniti has "a lot of priorities" - priorities that undoubtedly include an already-confirmed front-wheel-drive small hatchback/crossover.
The report also indicates that Infiniti has some aspirations for stretching its new Q50/Q60 range in a higher-performance direction to take on competitors like BMW and Audi, the latter being De Nysschen's former employer. There's far from a firm timetable offered, of course, with De Nysschen saying "someday in the future we will be able to offer more high performance versions [of Q50] than we have today... the dynamic capabilities of this platform are very significant. It can handle far higher power than the engines we are using at launch."

A look inside Infiniti's variable-compression engine

We're sympathetic to anyone who had trouble understanding what's going on with Infiniti's new variable-compression engine. While we got a full tech briefing on the novel VC-Turbo back in August, the visual aids were lacking. The cutaway engine Infiniti brought to the Paris show fixes all of that. You can thank the little green and pink lines on the cutaway for making the whole idea a little more clear. Click through the gallery to see two lines – one green and one pink – that represent the different strokes allowing for different compression ratios. Remember, the compression ratio is the amount of volume in the cylinder on intake compared to the amount at the end of the compression stroke. Leave more room at the end and you lower that ratio. The length of the stroke doesn't change with this system, but where it sits along the cylinder does. Hence those two lines. The variable compression ratio allows this new turbocharged engine to maximize fuel economy when the turbo isn't needed by raising the compression ratio. It will see its first use in the next Infiniti QX50 crossover, previewed by the QX Sport Inspiration concept that's also on display in Paris, and has performance targets of 268 horsepower and 288 pound-feet of torque. After, it will migrate to other Infiniti and Nissan vehicles, with transverse front-drive-based applications first in line. Eventually, it's likely to completely replace Nissan's corporate 3.5-liter V6. We'll be poking around the engine a little more in Paris today to try and get some more info. For now, enjoy those cutaway images and those friendly little lines. Featured Gallery Infiniti VC-Turbo engine cutaway View 14 Photos Paris Motor Show Infiniti Nissan Technology Emerging Technologies engine 2016 paris motor show