When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hard to cut through the marketing-speak to figure out how they’re actually implementing this. They advertise low compression as “high power” and high compression as “high efficiency”. I suppose that the lower compression lets them run more timing under boost.
Hard to tell if this is the beginning of the next VTEC revolution, or just a way for Infiniti meet federal emissions/efficiency standards. Anyone aware of this tech in high performance/ race engines?
OTOH, I think it’s cool that the regulations are driving some OEM innovation with turbo implementation.
Last edited by Schroedinger; 01-25-2018 at 08:53 PM.
That is neat. It took me a second to work out how it worked, but it's a hinged big-end with a second set of rods riding on a lobed secondary shaft. As the lobes twist, the secondary rods can lengthen or shorten the effective rod length which varies compression. It's also neat that the cylinders are no longer centered over the crankshaft.
The sad part is 268HP 2.0L turbo engine. That's about 100hp less than the 2.0L turbo engine in the CLA that was released a few years ago.
EDIT: Mercedes is 375hp, so actually just over 100hp more.
yeah, that's pretty obvious. Seems wasteful to put all that variable compression stuff and then not take advantage of it to improve HP or at least match the competition though. The merc is 10.5:1 compression all the time and 100hp higher output. I would assume the variable compression will win in economy for obvious reasons, just seems sad they can't even match or come close to HP from competitors who don't have that tech helping them.
I sat here playing with the compression toggle animation for a while. It definitely looks cool, but it sure seems like a lot of extra moving parts to break/wear out. Especially when other manufacturers are doing so much with head, injection, and ignition design that allows for such good results with high compression. It just seems like a lot of innovation where there isn't a ton of gain to be had.
I agree with you guys, but I think you're missing the point (or at least I'm seeing this in a different light, it seems): all these funky new engines and "technology" is them exploring new/more efficient options, not trying to set records. I dunno
I agree with you guys, but I think you're missing the point (or at least I'm seeing this in a different light, it seems): all these funky new engines and "technology" is them exploring new/more efficient options, not trying to set records. I dunno
You're right. They are taking the typical internet bro response.
18mpg in '88 to 23mpg in 2008.............................all the while cars have become heavier, more powerful, more optioned and safer................ummmm what's your point?
I would like too see the HP and torque vs. RPM plots for that Infiniti. I agree that their specified peak HP is underwhelming, but it may have a broader power band.
I think the limiting factor may be the mechanical limits of the variable compression mechanism. In a normal rod, the force is transmitted in a more or less straight line from the crankshaft to the piston pin. However, in the infinity engine, there's an offset in the middle of the rod, creating an enormous amount of torque about that joint, which also happens to be a complex mechanism with lots of small parts as opposed to a solid piece of cast iron. So it's possible that infinity erred on the safe side with a large design margin so that their new technology wouldn't get a bad rap.
*edit* I guess that's basically what Vlad said, so pardon my redundancy.
18mpg in '88 to 23mpg in 2008.............................all the while cars have become heavier, more powerful, more optioned and safer................ummmm what's your point?
agreed.
if the gubment wasn't mandating eleventy billion "mandatory" additions to cars, and if the market wasn't expecting/demanding every creature comfort under the sun, those numbers would increase drastically.
Ok Mr. OKC, I will not call those "excuses," but frankly MPG is the bottom line to me not one reason after another to burn more oil. I absolutely want to pay for the smallest amount of fuel and the smallest amount of money for a car for transportation that will be the most reliable and gets me where I'm going using the least amount of energy. Cars have not become more fuel efficient for decades, it's sugar coated hocus pocus. Cars from the 80s were better built and had better fuel economy, not all makes and models but some. They became worse in marked ways in following decades and engine tech is stagnant. It's time to get rid of petroleum engines altogether but they may be making an attempt at a swan song with fancy ICE buzz words as far as I'm concerned. It's cool from an engineering standpoint for sure, but trying to reinvent the piston engine is beating a long dead horse. Most everyone needs heat and transportation i.e. oil, but it would also be interesting to see what cooperation and incentives oil companies have with auto manufacturers it's easy to see they go hand in hand. If they report a legit 60, 70, 100+ MPG engine then it might be worth looking at.
This is up there with some of the stupider stuff that comes out of your mouth on a daily basis. Better built?
Let me cut you off at the pass before you bring up the might CRX HF..........lean burn engines aren't feasible anymore because of NOx limits for one, I'm not even going to bother to address idiotic claims like cars from the 80s were better built.
agreed.
if the gubment wasn't mandating eleventy billion "mandatory" additions to cars, and if the market wasn't expecting/demanding every creature comfort under the sun, those numbers would increase drastically.
One of my buddies has a new M2... BMW's "small and light" sports car. It weighs almost 3500 lbs. My other buddy has a Panamera Turbo, it weighs 450 pounds more than my Sienna minivan.
If you have ever felt like '88 was about when they stopped making cars fuel efficient this graph more or less backs that up:
It would be much better to see with min and max per year, etc.
The green line, Cars, gives us an increase of 1 MPG from 21 to 22 between 1990 and 2008.
Except that it doesnt. Scaling isn't hard. You've got a 3mpg increase from 90-08, not the 1mpg you point out.
And the graph clearly states that 88 is pretty much right when the improvements started to pick up consistently.
Last edited by concealer404; 01-26-2018 at 05:55 PM.
01-25-2018, 08:41 PM
Infiniti variable compression engine
1
