Variable Compression Engine

That looks ace, if expensive to build / maintain. Good luck to Nissan, as you sat it's about time we had some proper progress in the ICE world.
 
acemastr said:
http://jalopnik.com/worlds-first-variable-compression-ratio-engine-could-ki-1785295848

This looks amazing. This combined with pneumatic valves would just be incredibly efficient and powerful.

It's about time that something revolutionary came of the ICE, not just the bits around it (direct injection, hybrids etc)
Click to expand...

There was a concept some 30 years ago for a variable capacity engine which I thought was pretty good and might have provided similar benefits.

(Basically once off idle, the engine would match capacity to load ensuring high load factors, and therefore high efficiency, throughout the power range)

Unfortunately, all these "revolutionary" concepts tend to to go hand in hand with vastly increased complexity and vastly increased construction and repair costs.

ECU controlled valves sound nice in theory because of the potential improvements in performance and efficiency. Unfortunately it would only take a momentary glitch to stuff all the valves into the pistons and (for a modern vehicle) write the car off completely.

Perhaps I am somewhat jaundiced by my role as a mechanic (I only see stuff when it goes wrong after all) but I dont think anything has improved much since the early 90's (And in many ways much has gone backwards! :( )
 
Orionaut said:
There was a concept some 30 years ago for a variable capacity engine which I thought was pretty good and might have provided similar benefits.

(Basically once off idle, the engine would match capacity to load ensuring high load factors, and therefore high efficiency, throughout the power range)

Unfortunately, all these "revolutionary" concepts tend to to go hand in hand with vastly increased complexity and vastly increased construction and repair costs.

ECU controlled valves sound nice in theory because of the potential improvements in performance and efficiency. Unfortunately it would only take a momentary glitch to stuff all the valves into the pistons and (for a modern vehicle) write the car off completely.

Perhaps I am somewhat jaundiced by my role as a mechanic (I only see stuff when it goes wrong after all) but I dont think anything has improved much since the early 90's (And in many ways much has gone backwards! :( )
Click to expand...

Koenigsegg have developed a valve train system that is entirely camless and uses actuators, Pneumatic failure in their system means the valves open
 
Frozennova said:
Koenigsegg have developed a valve train system that is entirely camless and uses actuators, Pneumatic failure in their system means the valves open
Click to expand...

Surely "Open" valves would hit the pistons. (Bit like a timing belt failure)

(Unless the engine is designed to be free-wheeling (IE Even when valves are fully open the pistons cannot hit them))
 
Orionaut said:
Surely "Open" valves would hit the pistons. (Bit like a timing belt failure)

(Unless the engine is designed to be free-wheeling (IE Even when valves are fully open the pistons cannot hit them))
Click to expand...

Sorry meant closed, failure means there's no risk of damage.

Been a while since I watched the video but I think they claimed 30% improvements in power and economy when retrofitted to a run of the mill engine
 
Frozennova said:
Sorry meant closed, failure means there's no risk of damage.

Been a while since I watched the video but I think they claimed 30% improvements in power and economy when retrofitted to a run of the mill engine
Click to expand...

I am not talking about failure as such, more a software glitch or wiring problem.

Remember, it only has to happen "Once"!
 
muon said:
Well the Jalopnik headline is

The World's-First Variable Compression Ratio Engine Could Kill Diesel Forever
Click to expand...

A 14/1 compression ratio doesn't help the engine at all load and RPM ranges, variable will, so yes, it could feasibly beat a diesel once it's dialed in properly and designed for efficiency and not both power and efficiency
 
Wow, a whole 27% more efficient than a large displacement N/A V6. That's well worth the investment, production and maintenance costs.

Now compare it to a cylinder on demand turbo 4-pot.
 
Last edited:
I wonder how big an improvement an engine with this and the camless valve tech would be over the current conventional stuff. I'm guessing quite a lot.

They say this engine would actually be cheaper than equivalent turbodiesel engines? Please let this be true and end the dagdag menace. :p
 
paradigm said:
Wow, a whole 27% more efficient than a large displacement N/A V6. That's well worth the investment, production and maintenance costs.

Now compare it to a cylinder on demand turbo 4-pot.
Click to expand...

If real, a 27% improvement is huge. There's nothing stopping them combining this with cylinder deactivation either.
 
What? How is it "huge"? If it was a 27% improvement over a comparable "traditional" 2.0 4-pot, then yes, I'd agree. Comparing it to a different layout, with a different cylinder count, a different breathing method, and a massively different displacement is hardly ground-breaking.

Simply by buying in a Gen 3 EA888 VAG 2.0 petrol TFSI engine they could have had 48% fuel efficiency over the same 3.5l V6.
 
I "hope" you're (best engined) car doesn't. Blow up. Again as I can't afford to give you another 'tenner' for it
 
You must log in or register to reply here.
Back
Top Bottom