how is it working out- sounds complicated to me.
infinity variable compression engine
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https://www.infinitiusa.com/infiniti-now/technology/vc-turbo-engine.html
Scotty Kilmer hates it, but he hates every technology less than 20 years old.
Scotty Kilmer hates it, but he hates every technology less than 20 years old.
I read somewhere that the real-world fuel savings were disappointing, not enough to justify the cost and complexity of the new technology. Put me in Scotty's camp I guess.
Originally Posted by atikovi
https://www.infinitiusa.com/infiniti-now/technology/vc-turbo-engine.html
Scotty Kilmer hates it, but he hates every technology less than 20 years old.
Then Scottie should like it, the Nissan article says in development more than 20 years.
https://www.infinitiusa.com/infiniti-now/technology/vc-turbo-engine.html
Scotty Kilmer hates it, but he hates every technology less than 20 years old.
Then Scottie should like it, the Nissan article says in development more than 20 years.
"The more they overthink the plumbing, the easier it is to stop up the drain." From Space Shuttles to Nissan Sentra's the words of the galaxies best chief engineer
Montgomery Scott invariably prove to be true when given a long enough time scale.
Montgomery Scott invariably prove to be true when given a long enough time scale.
Seems like a fail compared to other competitors.
With Lister CS (cold start) diesel engines, they provided an external knob to raise the compression ratio. It was simply a valve that closed off a small chamber. Very simple and 100% reliable.
It's entirely possible to so something similar with gas engines. Using a device that changes position in the combustion chamber, to lower the compression ratio. The argument that it disrupts the combustion event is in error. Today's direct injection combustion chambers are chock-a-block full of unusual and sharp shapes designed to help direct injection function properly.
Remember spark plug spacers?
It's entirely possible to so something similar with gas engines. Using a device that changes position in the combustion chamber, to lower the compression ratio. The argument that it disrupts the combustion event is in error. Today's direct injection combustion chambers are chock-a-block full of unusual and sharp shapes designed to help direct injection function properly.
Remember spark plug spacers?
Kestas
Staff member
As Number_35 stated, It's probably cheaper to burn more fuel than deal with the complexity of this design.
The name of the game is not to save gas, it's to make travel from Point A to Point B as inexpensive as possible.
I suspect if the time comes when gas is so expensive that variable compression is economically justified, we'll have moved on to EVs.
The name of the game is not to save gas, it's to make travel from Point A to Point B as inexpensive as possible.
I suspect if the time comes when gas is so expensive that variable compression is economically justified, we'll have moved on to EVs.
The diesel system is simple and works on pressure dynamics, reducing combustion chamber size by partially obstructing it's volume using a manual valve which in turn raises compression. The Nissan VC works differently, variable compression way of variable stroke depth and an actuator motor. https://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/vc_turbo_engine.html
There's a reason even we Nissan/Infiniti enthusiasts joke about Nissan being the Chrysler of Japan.
There's a reason even we Nissan/Infiniti enthusiasts joke about Nissan being the Chrysler of Japan.
The thing I find interesting in that page is the 8:1 compression is for more power while 14:1 is for efficiency. Pretty much the opposite of established hot rodding practise of higher compression = more power.
Variable compression, variable valve lift and timing, variable boost turbo / super charger, etc all have the same goal: maximize fuel economy and power.
Until I see the long term result (i.e. 10 years, 100k miles), I am a bit skeptic. There has to be a reason why nobody else is doing it.
Until I see the long term result (i.e. 10 years, 100k miles), I am a bit skeptic. There has to be a reason why nobody else is doing it.
Originally Posted by atikovi
The thing I find interesting in that page is the 8:1 compression is for more power while 14:1 is for efficiency. Pretty much the opposite of established hot rodding practise of higher compression = more power.
You do not want to handle any turbo boost at 14:1, and you do not want to run 8:1 if you are just cruising the highway at 70mph.
The thing I find interesting in that page is the 8:1 compression is for more power while 14:1 is for efficiency. Pretty much the opposite of established hot rodding practise of higher compression = more power.
You do not want to handle any turbo boost at 14:1, and you do not want to run 8:1 if you are just cruising the highway at 70mph.
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Mazda had a much smarter plan by cooling the EGR gasses significantly, allowing them to not have to dump fuel to cool the cylinders. It worked very well, too in the real world, as most of us CX5 turbo owners see far better than EPA. I'm sitting on 26.4mpg lifetime, while the vehicle is only rated at 27 hwy. Just like Mazda said, it kills its EPA ratings. Most review magazines saw the same thing, with it getting 30+ doing 75 on the freeway.
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Early tech is always risky, but as they refine it over there years, the potential benefits are huge. Nissan engines have generally been pretty solid (increase in quality across the board since 2007+), the same can't be said for their CVTs, sadly.
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Infinity is in the toilet with sales. They had a 40% drop last month and pulled out of Europe.
Not sure why they bothered with this engine as it's not interesting to the average luxury buyer.
Not sure why they bothered with this engine as it's not interesting to the average luxury buyer.
I think this engine is now in the Altima as well. If we don't see huge failure numbers, it is probably a success. I think it is really more of a proof of concept that they can build upon if it works.
The VC Turbo has been out for about 3 years, most have under 60k miles on them and there are few examples with over 100k miles. Another 2-3 years and 30-45k miles avg on the engines will demonstrate (outside of warranty) how well those rotating assemblies in place of rods hold up. For comparison one can readily find cars with VQ35HR's and VQ37VHR's pushing 220-300k+ miles without a rebuild running well if the owner was diligent about changing coolant, oil and other fluids.
Originally Posted by GZRider
The diesel system is simple and works on pressure dynamics, reducing combustion chamber size by partially obstructing it's volume using a manual valve which in turn raises compression. The Nissan VC works differently, variable compression way of variable stroke depth and an actuator motor. https://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/vc_turbo_engine.html
There's a reason even we Nissan/Infiniti enthusiasts joke about Nissan being the Chrysler of Japan.
I always thoght Nissan was the Chrysler of Japan too, like Honda is Japan's GM and Toyota is the Japanese Ford.
The VC engine is mechanically more complex, but Nissan wanted to avoid Saab's experiment with variable compression. The Saab engine was a articulated block and head, which meant simple bottom end but a potential sealing failure point.
https://www.eeuroparts.com/blog/1270/saabs-variable-compression-engine-strange-live-rare-die/
The diesel system is simple and works on pressure dynamics, reducing combustion chamber size by partially obstructing it's volume using a manual valve which in turn raises compression. The Nissan VC works differently, variable compression way of variable stroke depth and an actuator motor. https://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/vc_turbo_engine.html
There's a reason even we Nissan/Infiniti enthusiasts joke about Nissan being the Chrysler of Japan.
I always thoght Nissan was the Chrysler of Japan too, like Honda is Japan's GM and Toyota is the Japanese Ford.
The VC engine is mechanically more complex, but Nissan wanted to avoid Saab's experiment with variable compression. The Saab engine was a articulated block and head, which meant simple bottom end but a potential sealing failure point.
https://www.eeuroparts.com/blog/1270/saabs-variable-compression-engine-strange-live-rare-die/
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