QOTD: Variable Displacement - New Hotness or Inevitable Blowout?

qotd variable displacement new hotness or inevitable blowout

At this week’s L.A. Auto Show and Traffic Negotiation Event, Infiniti will reveal the next generation QX50 — an overdue replacement for the aged model formerly known as the EX35. While the introduction of a crossover that’s losing its V6 and rear-wheel-drive platform wouldn’t normally interest me, the model’s new engine does.

Today we’re going to discuss variable displacement and the future of internal combustion engines. Fly or flop, what say you?

A little background is necessary, in case not all of you are avid readers of TTAC (like you should be). The upcoming QX50, set to appear in showrooms next summer, will come equipped with the first-ever variable displacement engine. Earlier in November, Matthew Guy did a nice job summarizing how the engine works.

Basically, the engine is able to alter the reach of the pistons, adjusting the compression ratio between 8:1 (for power) and 14:1 (for efficiency). This effectively alters the displacement of the engine on the fly. It’s never been done before. This leads me to today’s inquiry, and a few of the things I’ve been considering recently:

  • This is a major change for internal combustion engines, and the largest shift in piston engine function in the past hundred years. Will other manufacturers quickly follow Nissan’s lead, or shy away from this sort of bold engineering move?
  • Generally speaking, major tech advances in engine technology have often been accompanied by spotty reliability for a period of time after introduction. Eventually, the wrinkles are ironed out by the manufacturer, but by that time the majority of the public has rejected the technology. Does reliability in such a complex engine concern you? Or is Nissan, builder of VQ V6 engines, competent enough in that area to assuage your fears?
  • There’s always a risk that the market will not accept a “new way” of propelling a car. But perhaps the fuel economy promised by the technology will override any other concerns. Do you think this is the sort of engine the public is brave enough to purchase, assuming the idea of variable compression is something they can comprehend?

One more thing. Infiniti and Nissan are betting big on this technology’s success to ensure a return on their investment. After a development timeline of over 20 years, the company has decided against employing the engine on some high-end, limited-production halo car, installing it instead in a mid-market crossover which will theoretically sell many thousands of units. If it fails, it’s going to fail spectacularly and publicly. If it succeeds, it’s going to change the future of the Infiniti lineup at the very least, and perhaps passenger cars as a whole.

Use your crystal ball, B&B. What do you see in the future of the variable displacement engine?

[Image: Infiniti]

Comments
Join the conversation
2 of 53 comments
  • Newenthusiast Newenthusiast on Nov 29, 2017

    There's a lot of engineering talk here that I don't understand. I'd probably have to see ho it worked vs a traditional engine design to get it. That being said, I'm interested enough in what it promises to keep an eye on the reliability numbers on models with this engine going forward. Much like Mazda's SkyActiv - X, if it gives the models its used in a noticeable difference in fuel consumption, and it turns out to be otherwise an engine with no extreme reliability issues (no one is expecting perfection), then it's going to be a plus for shoppers who look at fuel efficiency and a non-issue for almost anyone else. If it works as they say it will, the question becomes will other automakers try to develop similar technology?

  • Rpn453 Rpn453 on Nov 30, 2017

    Good discussion here. It's not a vehicle that interests me (I doubt that Infiniti ever will sell another vehicle that interests me) but if I were asked for my opinion I'd simply recommend giving the technology some time to prove itself.

  • Arthur Dailey For the Hornet less expensive interior materials/finishings, decontent just a little, build it in North America and sell it for less and everyone should be happy with both the Dodge and the Alfa.
  • Bunkie I so wanted to love this car back in the day. At the time I owned a GT6+ and I was looking for something more modern. But, as they say, this car had *issues*. The first of which was the very high price premium for the V8. It was a several thousand dollar premium over the TR-7. The second was the absolutely awful fuel economy. That put me off the car and I bought a new RX-7 which, despite the thirsty rotary, still got better mileage and didn’t require premium fuel. I guess I wasn’t the only one who had this reaction because, two years later, I test-drove a leftover that had a $2,000 price cut. I don’t remember being impressed, the RX-7 had spoiled me with how easy it was to own. The TR-8 didn’t feel quick to me and it felt heavy. The first-gen RX was more in line with the idea of a light car that punched above its weight. I parted ways with both the GT6+ and the RX7 and, to this day, I miss them both.
  • Fred Where you going to build it? Even in Texas near Cat Springs they wanted to put up a country club for sport cars. People complained, mostly rich people who had weekend hobby farms. They said the noise would scare their cows. So they ended up in Dickinson, where they were more eager for development of any kind.
  • MaintenanceCosts I like the styling of this car inside and out, but not any of the powertrains. Give it the 4xe powertrain - or, better yet, a version of that powertrain with the 6-cylinder Hurricane - and I'd be very interested.
  • Daniel J I believe anyone, at any level, should get paid as much as the market will bear. Why should CEOs have capped salaries or compensation but middle management shouldn't? If companies support poor CEOs and poor CEOs keep getting rewarded, it's up to the consumer and investors to force that company to either get a better CEO or to reduce the salary of that CEO. What I find hilarious is that consumers will continue to support companies where the pay for the CEOs is very high. And the same people complain. I stopped buying from Amazon during the pandemic. Everyone happily buys from them but the CEO makes bank. Same way with Walmart and many other retailers. Tim Cook got 100m in compensation last year yet people line up to buy Iphones. People who complain and still buy the products must not really care that much.
Next