Nissan Motor Company has announced a new type of gasoline engine

Post by maxerickson » Mon, Aug 15, 2016, 2:18 AM UTC

shawkinaw wrote: post #11

From the (much better) Reuters article [0]: > The higher the ratio, the more efficiently the engine works, producing better fuel economy and, with the addition of a turbo-charger, more power. > Traditionally, design engineers had to fix a gasoline engine's combustion compression ratio, essentially deciding whether to go for power or economy. Everything gets better with higher compression ratio, so where's the comprom…

Post by seanp2k2 » Mon, Aug 15, 2016, 2:19 AM UTC

paulmd wrote: post #18

Aelinsaar wrote: post #13

Earlier quoted context omitted.

The drawback is that higher compression ratios require higher octane fuels. Nissan claims to have solved this by some kind of intelligent feedback system that allows them to control compression ratios on the fly. Presumably the compromise there is that it will require more moving parts, be expensive, and may come with issues of its own. Variability in something like a combustion chamber is a cool idea, so is variabil…

The obvious precedent for variable-pitch blades are variable-pitch propellers on aircraft and helicopters. I don't want to say it's a solved problem for turbos, but there is almost a century's worth of prior art on the topic. That's one of those things that (in hindsight) really makes you wonder what took so long to think up. https://en.wikipedia.org/wiki/Variable-pitch_propeller

Post by Aelinsaar » Mon, Aug 15, 2016, 2:20 AM UTC

shawkinaw wrote: post #21

Aelinsaar wrote: post #13

Earlier quoted context omitted.

The drawback is that higher compression ratios require higher octane fuels. Nissan claims to have solved this by some kind of intelligent feedback system that allows them to control compression ratios on the fly. Presumably the compromise there is that it will require more moving parts, be expensive, and may come with issues of its own. Variability in something like a combustion chamber is a cool idea, so is variabil…

Right, I figured this must actually be an anti-knocking technology. My point was just that the quote implied power and economy are optimized by taking the compression ratio in different directions, which is wrong.

Post by brownbat » Mon, Aug 15, 2016, 2:21 AM UTC

bmh_ca wrote: post #15

brownbat wrote: post #12

I have a lot of respect for Nissan's engineers, but somewhat less respect for their lawyers, who hounded Uzi Nissan for a decade trying to get him to turn over his domain. http://www.nissan.com/Lawsuit/The_Story.php Cybersquatting is obnoxious, but once they found out it was the guy's actual name, and that he was using it to run his own business, they should have just accepted he had a right to the site and worked to…

Lawyers are tools. (Being one, I feel I can say so, with a humble degree of confidence.) Certainly there's a give-and-take between lawyers giving advice and clients taking it, but by the "big X" their lawyers essentially do what they are told - lest the big client move elsewhere. All to say: Lawyers doing a bad thing are often a symptom of an internal disease or conflict. Which is to summarize a whole host of conflic…

Post by sliverstorm » Mon, Aug 15, 2016, 2:21 AM UTC

Aelinsaar wrote: post #13

shawkinaw wrote: post #11

From the (much better) Reuters article [0]: > The higher the ratio, the more efficiently the engine works, producing better fuel economy and, with the addition of a turbo-charger, more power. > Traditionally, design engineers had to fix a gasoline engine's combustion compression ratio, essentially deciding whether to go for power or economy. Everything gets better with higher compression ratio, so where's the comprom…

The drawback is that higher compression ratios require higher octane fuels. Nissan claims to have solved this by some kind of intelligent feedback system that allows them to control compression ratios on the fly. Presumably the compromise there is that it will require more moving parts, be expensive, and may come with issues of its own. Variability in something like a combustion chamber is a cool idea, so is variabil…