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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

#81

Post by semi-extrinsic »

asimuvPR wrote: post #63
micaksica wrote: post #55

Earlier quoted context omitted.

> Possible issues with this design could be: Let's also recognize that shortblock costs will be much, much higher with this design when you need a rebuild. Many engine builders won't touch this, and I'd suspect the Nissan OEMs will say that these engine shortblocks are "factory replaceable only". Who is going to make aftermarket bearings for the multilink setup? How does the engine operate under actuator failure?

I figure these engines won't be rebuilt. Its simpler to swap one in since its a four cylinder. The engine should operate OK in case the actuator stops adjust the stroke. There really isn't anything new in terms of parts. They simply took proven implementations of each part and applied them in a new configuration. The biggest issue might be cylinder bore degradation due to the variable stroke. I need to learn more abo…

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.

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

#82

Post by icebraining »

Reason077 wrote: post #75
icebraining wrote: post #74

Earlier quoted context omitted.

How do they pass the emissions test?

In the UK, there is no emissions test for particulate or NOx emissions, other than the subjective "does it emit visible smoke?". A visual inspection for the presence of the DPF is required, but this is easily defeated by installing a look-alike "null" filter. The people doing the MOT testing can be pretty shady anyway. Since any mechanic can operate as a testing facility, it's often the same people who remove DPFs th…

Seems like fixing that system would be more sensible than outlawing diesel cars, no?

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

#83

Post by ArkyBeagle »

jacknews wrote: post #51

This looks cool, but complicated. The problem addressed seems to be that turbocharged (and supercharged) engines are sub-optimal at lower powers. IMHO mild electric hybrids, or full serial electric hybrids would be a more elegant solution - only run the combustion engine when full power is needed, and use the electric motor otherwise. "full power" could be used to top the battery if it's not all required for motion.

Turbocharging and supercharging grew up in aviation , where there is much more variable air pressure due to altitude. They were more a "hack" to get more envelope out of an engine system. Started seeing them on consumer ground vehicles in the '80s, when everything had to have a "turbo" button because PCs had one.

It's never been clear to me that they are really all the great of a fit with terrestrial engines. Part count goes up, heat goes way up in spots and there is of course lag.

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

#84

Post by ArkyBeagle »

dclowd9901 wrote: post #53
jacknews wrote: post #51

This looks cool, but complicated. The problem addressed seems to be that turbocharged (and supercharged) engines are sub-optimal at lower powers. IMHO mild electric hybrids, or full serial electric hybrids would be a more elegant solution - only run the combustion engine when full power is needed, and use the electric motor otherwise. "full power" could be used to top the battery if it's not all required for motion.

Would an electrically powered, computer-controlled turbo be silly?

The electric motor to be used would have to be a pretty unusual motor. IMO, supercharging is "better" because the PTO side of an engine is less ... trouble than the exhaust side. Superchargers are generally heavier.

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

#85

Post by jmus »

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…

I had to chuckle at your first sentence. Over here (UK) 'tool' is often used in slang as a derogatory term for a person, effectively likening them to an obvious part of the male anatomy...

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

#86

Post by asimuvPR »

semi-extrinsic wrote: post #81
asimuvPR wrote: post #63

Earlier quoted context omitted.

I figure these engines won't be rebuilt. Its simpler to swap one in since its a four cylinder. The engine should operate OK in case the actuator stops adjust the stroke. There really isn't anything new in terms of parts. They simply took proven implementations of each part and applied them in a new configuration. The biggest issue might be cylinder bore degradation due to the variable stroke. I need to learn more abo…

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.

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

#87

Post by Annatar »

dredmorbius wrote: post #37
Sanddancer wrote: post #33

I'm curious as to what, if anything, would preclude variable displacement from being used in diesels as well as petrol engines. Diesels also have performance/economy tradeoffs like this gasoline engines, so it stands to reason that tweaking compression should give similar benefit. I've got a feeling that rumors of diesel's impending demise are greatly exaggerated.

Diesel's fatal flaw is particulate emissions. Attempts to mitigate those, without cheating (e.g., VW), have proven difficult.

Difficult, yes, but doable: mazda's SKY-D diesel features 14:1 compression and Tier II Bin 5 / Euro VI compliant emissions without Urea. The lower emissions were achieved by lowering the compression ratio and lengthening the exhaust manifold, so that the exhaust gasses can cool. As the result, mazda is the only manufacturer selling diesel passenger cars in Japan.

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

#88

Post by Reason077 »

icebraining wrote: post #82
Reason077 wrote: post #75

Earlier quoted context omitted.

In the UK, there is no emissions test for particulate or NOx emissions, other than the subjective "does it emit visible smoke?". A visual inspection for the presence of the DPF is required, but this is easily defeated by installing a look-alike "null" filter. The people doing the MOT testing can be pretty shady anyway. Since any mechanic can operate as a testing facility, it's often the same people who remove DPFs th…

Seems like fixing that system would be more sensible than outlawing diesel cars, no?

I agree with you. A strict emissions test regime would be a good first step. But politicians have known about this for years and little has been done - apparently it's a too hard (or too expensive) problem to fix.

The thing is, even brand-new "clean" diesels are still worse polluters, for toxic particulates and NOx, compared to petrol and petrol-electric hybrid vehicles.

London already has a disincentive on diesels coming into effect by 2019, when pre-Euro 6 (i.e. older than September 2015) diesel vehicles will be subject to a £12.50/day charge to drive in London.

There are calls to extend this to cover all diesel vehicles, eventually leading to a total ban:

https://www.theguardian.com/environment/2016/jul/18/ban-dies...

Licensing of new diesel taxis will also soon be prohibited in London, and all single-deck busses will be zero-emission by 2020 (and double-deck busses will, at minimum, be hybrids).

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

#89

Post by wepple »

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…

Under certain conditions (high load, warm day), you'll start hearing a 'pinging' sound on high-compression engines; that's the air/fuel mixture pre-igniting before it is supposed to (before the spark fires) essentially turning the engine into a wannabe diesel and ruining performance/efficiency.

There are a few other undesirable things about high-compression.

And I just read your message about knocking. same thing. Nevermind.

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

#90

Post by SixSigma »

In economics, the Jevons paradox occurs when technological progress increases the efficiency with which a resource is used (reducing the amount necessary for any one use), but the rate of consumption of that resource rises because of increasing demand.

https://en.wikipedia.org/wiki/Jevons_paradox

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