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Nissan Motor Company has announced a new type of gasoline engine

reuters.com

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Re: Nissan Motor Company has announced a new type of gasoline engine

#111

Post by semi-extrinsic »

asimuvPR wrote: post #86
semi-extrinsic wrote: post #81

Earlier quoted context omitted.

Realistically, how often is a petrol I4 engine rebuilt in consumer cars? I've seen 1980's Volvo redblock engines with 300k miles on them run as smooth as butter. Short of neglecting timing belt changes, running without oil, or incompetent modifications, nothing much kills a petrol engine before the rest of the car is scrap.

Depends on the brand. Nissan engine quality has gone down in the last 15 years. Their flagship engine the VQ3XDETT has been good but the rest of the lineup has suffered. Its not yet as cas as a chrysler9 engine, but its not what it was during the 80s and 90s.

The VQ3XDETTs are used in the GT-R, no? That's a sweet engine for sure, I'm not surprised that a lot more engineering has gone into it compared to something like the MR16DE.

Re: Nissan Motor Company has announced a new type of gasoline engine

#112

Post by sandworm101 »

usrusr wrote: post #70
tapeman wrote: post #48

Earlier quoted context omitted.

That article is kind of shitty too. Higher compression ratio = better combustion = more power with less fuel, regardless of turbo. Higher compression will always mean better fuel efficiency. My moms Mazda CX-5 runs a 13.5 compression ratio and gets 27mpg. The power/efficiency trade off appears when you're talking about turbocharged engines. Turbos compress air into the combustion chamber, so when you compress compres…

So this only reduces inefficiency while the the engine revs too low for the turbo to kick in? Then it is competing with electrically assisted turbocharging (spin the turbo electrically when there is not enough exhaust pressure, basically a super/turbo hybrid using electric transmission), as both are addressing the same inefficiency. I know where I would put my bets in terms of price, reliability and ease of developme…

>> while the the engine revs too low for the turbo to kick in?

This is a common misconception of 'turbo lag'. A modern turbo is actually operating at the low revs too. The boost is there. But a modern turbo engine, especially a diesel, has a very narrow powerband, giving the impression that the turbo isn't active until higher rpms. This isn't real 'turbo lag'. Real 'turbo lag' is the delay caused by the fact that the turbo depends on exhaust pressures, which rise only momentarily after throttle increases. But this problem has largely been solved via mutli-stage turbos, lighter turbo parts, waste gates and the like. Real turbo lag, where it is noticeable, occurs at all rpm ranges.

Re: Nissan Motor Company has announced a new type of gasoline engine

#114

Post by larrydag »

asimuvPR wrote: post #31

Here is a simple explanation gathered from this image http://o.aolcdn.com/hss/storage/midas/de3e84cf46030cd7b3ea39... : The difference from a conventional engine is that the engine stroke is increased or decreased automatically. The stroke is the distance the piston travels up and down in order to turn the crankshaft. A shorter distance that is closer to the combustion chamber increases the compression ratio because…

Clever design but that looks like a lot of moving parts. I wonder about longevity of the engine.

Re: Nissan Motor Company has announced a new type of gasoline engine

#116

Post by lutefisk »

codeulike wrote: post #113

This is all moot. Battery technology and charging infrastructure for EVs will improve so much over the next 5 to 10 years that engines running on dinosaur juice will no longer be worth the hassle for mainstream vehicles.

So all companies related to gas technology should just close up shop? Something that may or may not work is on the horizon, so all the engineers that have been researching gas technology for years should throw in the towel and quit? There is no chance that electric overtakes gas in 5 years.

Re: Nissan Motor Company has announced a new type of gasoline engine

#117

Post by codeulike »

lutefisk wrote: post #116
codeulike wrote: post #113

This is all moot. Battery technology and charging infrastructure for EVs will improve so much over the next 5 to 10 years that engines running on dinosaur juice will no longer be worth the hassle for mainstream vehicles.

So all companies related to gas technology should just close up shop? Something that may or may not work is on the horizon, so all the engineers that have been researching gas technology for years should throw in the towel and quit? There is no chance that electric overtakes gas in 5 years.

er, electric cars work fine. They just need to get cheaper and have longer range. That will happen easily in the next 5 to 10 years.

Re: Nissan Motor Company has announced a new type of gasoline engine

#118

Post by asimuvPR »

semi-extrinsic wrote: post #111
asimuvPR wrote: post #86

Earlier quoted context omitted.

Depends on the brand. Nissan engine quality has gone down in the last 15 years. Their flagship engine the VQ3XDETT has been good but the rest of the lineup has suffered. Its not yet as cas as a chrysler9 engine, but its not what it was during the 80s and 90s.

The VQ3XDETTs are used in the GT-R, no? That's a sweet engine for sure, I'm not surprised that a lot more engineering has gone into it compared to something like the MR16DE.

Yes, it is the one from the GT-R. Nissan used to over-engineer their smaller engines. The SR20 engine family was built to handle boost across all models. It made them very durable.

Re: Nissan Motor Company has announced a new type of gasoline engine

#119

Post by Aelinsaar »

sliverstorm wrote: post #35
Aelinsaar wrote: post #32

Earlier quoted context omitted.

There are presumably still limits that this addresses, right? Please correct me if I'm wrong, I'd like to learn.

I suspect it does two things- 1) lets the engine have high compression AND a turbo. Typically a turbo is run with lower compression, because even today nobody can make an engine run 14:1 with a turbo. Speculating, when you floor it the compression might drop to 8:1 and the turbo kicks in; then when you highway cruise, it runs 14:1 for efficiency. 2) lets the little engine still hit big torque numbers at low speeds. T…

Ahhhh, those both make a lot of sense. This could be a nice feature on higher-end cars that try to use smaller engines, with more turbos, for the sake of fuel and emissions then?

Re: Nissan Motor Company has announced a new type of gasoline engine

#120

Post by ruste »

tonylemesmer wrote: post #97

So if this engine changes the compression ratio (the amount the mixture is compressed) how is all this complexity better than a supercharger which changes the amount the air is compressed? Surely increasing the compression of the mixture and compressing the air before it goes in is pretty much the same thing? Except...that all that variable stroke length mechanism is a lot more complicated, and patentable?

Higher compression ratio allows better fuel efficiency. Supercharging forces more fuel and air into the same cylinder.
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