Author Topic: Nissan Variable comp. ratio engine  (Read 288 times)

Offline Jules

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Nissan Variable comp. ratio engine
« on: 28.05. 2022 01:42 »
Hi all, I've been looking at new cars lately (cant buy them but can still look LOL!) and came across the new Nissans with this engine....
https://www.nissan-global.com/EN/INNOVATION/TECHNOLOGY/ARCHIVE/VC_TURBO_ENGINE/
I'm quite surprised at the investment when all other work is focused on EV's, but its interesting to read that the IC engine does still have some future (maybe?). I read about the Atkinson cycle (as opposed to the conventional Otto cycle we are all familiar with) quite a lot now wrt hybrid vehicles and that works ok because it has the electric motor to overcome the power/torque loss, now if you add in variable CR too, it must make the IC engine sooo much more efficient (and complicated!)....

Offline Swarfcut

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Re: Nissan Variable comp. ratio engine
« Reply #1 on: 28.05. 2022 07:25 »
 Another innovative development of the Otto Cycle is the Miller Cycle, which uses a different inlet valve timing in conjunction with a Turbo. This dates from the mid 1950's and has found modern day application in the quest for fuel efficiency rather than outright power.

 Atkinson also has a variant, the Budack Cycle developed by VW, whose vehicles can pass tests better than I can....

 That Nissan design is almost too clever for its own good.

 Despite the move to electric, I can't see petroleum losing its grip overnight, but I will admit I'm using my vehicles in a different way and thinking more about whether I  really need to make that journey.  The fuel price is a factor, but also a nod towards lowering my carbon footprint.

 Swarfy

Offline BSA_54A10

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Re: Nissan Variable comp. ratio engine
« Reply #2 on: 28.05. 2022 08:30 »
The large car companies know that the entire EV thing is a virtue signaling scam and we can not replace all IC engines with EV's
Thus there will be more work on making them more fuel efficient
The factories try to follow the trends which for the past 50 years was bigger testicles
Now that what was predicted 50 yers ago is becomming apparent the fashion has chaged to more effiency , lower emissions .
No future in making vehicles that the market will not buy .

My fear is after all of the Ic engines have been trashed & we get 90% of electricity from a renewalable source but the climate continues to get worse people will not be willing to do what really matters.
Fewer children & longer life durable products .
Bike Beesa
Trevor

Offline Jules

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Re: Nissan Variable comp. ratio engine
« Reply #3 on: 28.05. 2022 09:04 »
More complicated indeed Swarfy but the design logic makes sense, if it can sustain the durability....and I agree Trevor, (I'm ex car industry) my fear is that the EV "revolution" is far too knee jerk and hasn't been thought through adequately wrt sustainability and recyclability. The future holds everything onto electricity and while its sort of sustainable, its not really when it has to support everything, wind and solar are really good supplements, but are completely inadequate for base/continous power loads, we have yet to find a true replacement for that before we can switch over everything confidently.
Even our own households have backup systems currently ie electric and gas and solid fuel and diesel/petrol and but all these need carbon to perform, once we go all (carbon free) electric where are the backups??? (please dont say batteries... *eek*)

Online Greybeard

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Re: Nissan Variable comp. ratio engine
« Reply #4 on: 28.05. 2022 09:49 »
Our car is a Honda Jazz, with a hybrid power train. The IC engine is an Atkinson unit. We are averaging over 50mpg overall and on some journeys getting over 70mpg.
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Online Rex

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Re: Nissan Variable comp. ratio engine
« Reply #5 on: 28.05. 2022 09:58 »
& we get 90% of electricity from a renewalable source

That'll be the day. We need to find the Holy Grail of efficient and sufficient energy storage first, and that's as distant as ever.

Offline BSA_54A10

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Re: Nissan Variable comp. ratio engine
« Reply #6 on: 29.05. 2022 07:09 »
& we get 90% of electricity from a renewalable source

That'll be the day. We need to find the Holy Grail of efficient and sufficient energy storage first, and that's as distant as ever.

Closer than you think Rex
The Flow cell batteries can supply reliable back up power at very high dischargerates and run till fully flat then fully recharged  with almost no capacity loss
Down side is because of the low volume of productoion they are expensive but could be 75% cheaper if they go into mass production .
However to be used efficiently they need to be in micro grids where the power is needed and not out in the sticks where space is cheap.
Plus of cource they are still batteries so they do have a capacity limit.
To be sustainable the entire grid needs to be configured and that is very big bickies that no one will want to pay for.

The liquid salt reactors , again in micro grids are the only current technology that looks to be viable but no one will want a reactor next to their house no matter how small or safe it is .
And of course you have the problem of investor returns.
Easy with a small nuumber of generators powering a massive grid.
A lot more difficult with a lot of small generators powereing a massive number of local grids with interconnectors .

It is portable power that is always going to be the problem & Lithium is not the answer for heavy current provision .
Way way back a paper on roof top solar calculated that in Sydney Australia alone there is sufficient roof tops correctly oriented to generate enough power to supply the entire Australian grid .
The problem is stabilizing the grid and of course supplying power when like last week the entire east coast is under cloud cover .
The worked model had local roof tops connected to a local battery and the batteries connected to the national grid .
And that was back in 2000 since when solar technology has advaned so far as to now be able to produce small amounts of power during the night.

The idea of hydrolizing water then burning the H & O at a latter date has been around for decades .
Back in the 60's when I was at UNSW the Uni had functioning power plants on almost everybuilding plus a pilot ( research ) plant at Fiji where of course the professors & post grads could fly at tax payer expense to carry on the "research " .
But the national White paper on Australian energy was all about sucking gas out of the ground for the purpose of making massive profits ( and of course tax revenue ) and not about making regions self sufficiet .
So no reason what so ever not to build direct fired turbine Hydrogen powered generators on the site of old coal fired power stations running on Hydrogen derrived from solar powered hydrolysis plants  .
A few years back the CSIRO actually presented a paper to the Aust governement with a policy of converting the power stations in the Latrobe valley to syngas , derrived from burning the brown coal under water  which reduces the pollution nearly 50 % as comparred to burning in open cell furnaces & usuing reflected radiation to boil water . Then progressively converting the generators to direct fired turbines and eventually powering them with strait hydrogen .
The grid was to be balanced by diverting all of Melbourne's sewerage to there and processing through membrane filters thus making it potable water
So we solved 3 problems in one hit
Cleaner power generation
sewerage pollution
water restrictions

But the looney Victorian ( in more ways than geography ) Greenies would not have a bar of it they were fixiated on their goal to demolish Hazelwood as if this was some fanstic world shattering achievment so the plan got poo pooed and ignorred .
Bike Beesa
Trevor

Online Rex

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Re: Nissan Variable comp. ratio engine
« Reply #7 on: 29.05. 2022 08:40 »
Yeah, I know, but very few months someone claims to have invented some sort of storage concept and it's going to be wonderful blah blah, but if/when it is actually proven to be a workable system it'll be front page news.
Some dick in his garden shed or an undergraduate in his Uni research lab isn't likely to hit on the magic golden goose any time soon, sadly.
Filling the landscape with solar panels is the easy part, sufficient storage of juice for the cold Winter nights (and ever-increasing electric vehicles) is still merely a distant dream.

Offline BSA_54A10

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Re: Nissan Variable comp. ratio engine
« Reply #8 on: 30.05. 2022 14:11 »
When you have a minute check out flow cell batteries .
I had never heard of them till there was talk of going off gring on another forum
One member mentioned that his set up was so good he was adding a second Redflow battery which would be big enough to power the house & workshop for a full week .
Not cheap in any way shape or form but with some governemnt support could very well be a lot cheaper .
A big difference from powering a house & small workshop to powereing an entire city but doable if done on a micro grid basis so you don;t need a batttery array bigger than the Opera House 200 miles away from where the power is needed .
In theory you should be able to run a power cable right round the planet .
There is a plan for Chna to export solar generated power into Europe and apparently Huang Ming's Sun City in DeZhou China is 100% powered from wind ,solar & stored thermal and that was back in 2018 when it was a tiny 1/2 million and this city is unique as all of it is generated within the city and stage II which will take the city to a full million is almost complete .
Then there is Rizhao, a city of 3 million fully solar powered however they are using mainly solar farms outside the city limits rather than roof top power
The dfference is the former was done by a single person where as the latter was a retrofit & already had grid power .

So there really is no reason why it can not be done
What is stopping it is protecting the financial interests of the privatised power generators ( that was a stupid idea ) and paying for the new grid .
Bike Beesa
Trevor