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Infiniti First to Market with Variable Compression Engine ? #4588633
11/29/17 10:36 AM
11/29/17 10:36 AM
Joined: Jan 2006
Posts: 2,693
Idaho
SubLGT Offline OP
SubLGT  Offline OP
Joined: Jan 2006
Posts: 2,693
Idaho
Quote:
...At the Los Angeles Auto Show, INFINITI revealed the all-new QX50—a premium mid-size SUV featuring the first production application of the VC-Turbo variable compression ratio engine, transforming on demand…

...The VC-Turbo changes its compression ratio seamlessly with an advanced multi-link system, continuously raising or lowering the pistons’ reach to transform compression ratio—offering both power and efficiency, on demand….

...As the angle of the multi-link arms changes, it adjusts the top-dead-center position of the pistons—and the compression ratio with them. An eccentric control shaft changes the compression ratio of all the cylinders at the same time. As a result, the engine capacity varies between 1,997 cc (for a low 8:1 ratio) and 1,970 cc (high 14:1 ratio)….

...Equipped with the VC-Turbo engine, the QX50 delivers gasoline fuel economy of 27 mpg (US combined, front-wheel drive; 26 mpg all-wheel drive). In front-wheel drive specification, this offers a 35% improvement in fuel efficiency over the V6 gasoline engine in the previous QX50, while the new all-wheel drive model’s 26 mpg represents a 30% improvement...


More technical details here:
http://www.greencarcongress.com/2017/11/20171129-qx50.html

Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4588651
11/29/17 10:51 AM
11/29/17 10:51 AM
Joined: Mar 2017
Posts: 6,542
...
PimTac Offline
PimTac  Offline
Joined: Mar 2017
Posts: 6,542
...
As I understand it, the Mazda SkyActiv can change its compression ratio depending on certain circumstances. It may be more common than we know.


Cannot see signatures any longer so it doesn’t matter.
Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4588655
11/29/17 10:53 AM
11/29/17 10:53 AM
Joined: Sep 2004
Posts: 7,829
Marshfield , MA
andyd Offline
andyd  Offline
Joined: Sep 2004
Posts: 7,829
Marshfield , MA
There are too many extra reciprocating parts in there to make me comfortable. The 4 banger in my Camry gets 35.7 MPG in a 25~ mile drive to my daughter's house. I'm happy with that.


'16 Camry LE STP synth 0w20 and STP filter. the Fridge

1994 Ranger ,the Rat, 5w30 dino, STP filter

'16 Camry SE, Valvoline HM 0w20 and OEM filter
Thick oil is better grin2
Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4588669
11/29/17 11:01 AM
11/29/17 11:01 AM
Joined: Mar 2017
Posts: 6,542
...
PimTac Offline
PimTac  Offline
Joined: Mar 2017
Posts: 6,542
...
Reading that insert further this is a different way than what I was thinking. Mazda just keeps valves open at certain points in the combustion process to achieve the effect. Infiniti is going with a complicated method involving the rods. I would be cautious yet I applaud Infiniti for their innovation.


Cannot see signatures any longer so it doesn’t matter.
Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4588671
11/29/17 11:03 AM
11/29/17 11:03 AM
Joined: Aug 2008
Posts: 21,314
ON, Canada eh?
StevieC Offline
StevieC  Offline
Joined: Aug 2008
Posts: 21,314
ON, Canada eh?
I will wait until Nissan (Infinity) has their failures like early CVT's first and then when the bugs are worked out have a look.


'18 Dodge Grand Caravan GT - AMSOIL SS 5w20
'06 Santa Fe - 535,000km AMSOIL SS 0w30 / ATF
Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4588695
11/29/17 11:17 AM
11/29/17 11:17 AM
Joined: Feb 2007
Posts: 3,702
Southeast
meep Online content
meep  Online Content
Joined: Feb 2007
Posts: 3,702
Southeast
I really like the skyactive solution. lots of moving parts in the infinity design. I wonder if infinity found a wider performance/efficiency range or other advantage with their design? There's got to be additional losses from the multiple friction points and inertial mass, so there must be another payoff. I tell you what, when one of those throws a rod, the carnage will be unmatched.


2018 F150
2015 crv (wifey!)
Re: Infiniti First to Market with Variable Compression Engine ? [Re: andyd] #4588712
11/29/17 11:27 AM
11/29/17 11:27 AM
Joined: Dec 2016
Posts: 7,191
Waco, TX
Linctex Offline
Linctex  Offline
Joined: Dec 2016
Posts: 7,191
Waco, TX
Originally Posted By: andyd
There are too many extra reciprocating parts in there to make me comfortable.


1000's and 1000's of reliable flight hours say your fears are unwarranted



"The evidence demands a verdict".
(Re:VOA)"it's nearly impossible to actually know the particular additives that are in there at what concentrations."
Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4588715
11/29/17 11:30 AM
11/29/17 11:30 AM
Joined: Aug 2008
Posts: 21,314
ON, Canada eh?
StevieC Offline
StevieC  Offline
Joined: Aug 2008
Posts: 21,314
ON, Canada eh?
Nissan doesn't build aircraft and I'm thankful! LOL

Last edited by StevieC; 11/29/17 11:31 AM.

'18 Dodge Grand Caravan GT - AMSOIL SS 5w20
'06 Santa Fe - 535,000km AMSOIL SS 0w30 / ATF
Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4588853
11/29/17 01:02 PM
11/29/17 01:02 PM
Joined: Jun 2005
Posts: 5,278
North Texas
ARB1977 Offline
ARB1977  Offline
Joined: Jun 2005
Posts: 5,278
North Texas
Since turbos are more common now and days. How about variable waste gates. More psi when needed. Instead of reaching a certain psi to releave pressure.


2015 Tacoma 4.0L 60K (as of 02/23/18)
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2018 CRV 1.5L (as of 05/11/18)
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Re: Infiniti First to Market with Variable Compression Engine ? [Re: Linctex] #4589358
11/29/17 09:17 PM
11/29/17 09:17 PM
Joined: Sep 2004
Posts: 7,829
Marshfield , MA
andyd Offline
andyd  Offline
Joined: Sep 2004
Posts: 7,829
Marshfield , MA
Originally Posted By: Linctex
Originally Posted By: andyd
There are too many extra reciprocating parts in there to make me comfortable.


1000's and 1000's of reliable flight hours say your fears are unwarranted

This design is used in airplane engines? I didn't know that. Please elaborate.


'16 Camry LE STP synth 0w20 and STP filter. the Fridge

1994 Ranger ,the Rat, 5w30 dino, STP filter

'16 Camry SE, Valvoline HM 0w20 and OEM filter
Thick oil is better grin2
Re: Infiniti First to Market with Variable Compression Engine ? [Re: ARB1977] #4589503
11/30/17 01:19 AM
11/30/17 01:19 AM
Joined: May 2012
Posts: 5,683
Fort Lauderdale, FL
DoubleWasp Offline
DoubleWasp  Offline
Joined: May 2012
Posts: 5,683
Fort Lauderdale, FL
Originally Posted By: ARB1977
Since turbos are more common now and days. How about variable waste gates. More psi when needed. Instead of reaching a certain psi to releave pressure.


That's been done for a long time. Some vehicles change the boost pattern based on settings, and some based on atmospheric conditions.

I remember one of the rags doing a high altitude test of "hot" wagons, and the SAAB was walking away from a 540i wagon due it's boost pressure having elevated to 28psi to compensate for the lower air density.


07 Lincoln Navigator M1 0w-40/FU
68 Charger R/T / Supercharged 440 VR1/DBL7349
07 Ram 3500 4x4 / Cummins 6.7 /DBL7349
17 Maserati GranTurismo Cabrio
Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4589512
11/30/17 02:14 AM
11/30/17 02:14 AM
Joined: Dec 2002
Posts: 41,576
'Stralia
Shannow Offline
Shannow  Offline
Joined: Dec 2002
Posts: 41,576
'Stralia
I remember 1980s magazine articles on Nissan working on that engine...it's been in development for a LONG time

Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4590403
11/30/17 09:16 PM
11/30/17 09:16 PM
Joined: Jan 2009
Posts: 1,328
Watertown, New York
cronk Offline
cronk  Offline
Joined: Jan 2009
Posts: 1,328
Watertown, New York
It is certainly an interesting concept. Variable compression along with variable valve timing could really optimize efficiency and power.
If this design proves reliable it could really be a game changer. I would definitely let someone else buy one and be the Guinea pig to test reliability!


2008 Ford F350
2003 Chevy Cavalier
2011 Nissan Quest
1986 Pontiac Trans Am
1940 Ford 9N Tractor
Amsoil lubes and filters!
Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4590438
11/30/17 10:07 PM
11/30/17 10:07 PM
Joined: Jan 2007
Posts: 17,501
Clovis, CA
Merkava_4 Offline
Merkava_4  Offline
Joined: Jan 2007
Posts: 17,501
Clovis, CA
- variable compression
- variable valve timing
- multiple cylinder deactivation
- direct fuel injection

That should be a nice reliable engine. crazy crazy

Re: Infiniti First to Market with Variable Compression Engine ? [Re: SubLGT] #4590759
12/01/17 09:19 AM
12/01/17 09:19 AM
Joined: Aug 2008
Posts: 21,314
ON, Canada eh?
StevieC Offline
StevieC  Offline
Joined: Aug 2008
Posts: 21,314
ON, Canada eh?
Just needs a CVT! LOL


'18 Dodge Grand Caravan GT - AMSOIL SS 5w20
'06 Santa Fe - 535,000km AMSOIL SS 0w30 / ATF
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