Question To All The Gearheads?

[carzes]

What are the biggest advances in engine technology that will improve performance and mileage in the new Elio engine .

I can't answer as a gearhead but as a fellow who has watched from the sidelines, the biggest surprise to me is them designing an engine that can get a 11:1 compression ration out of regular 87 octane gasoline

Jim

Higher compression = better efficiency, but as I understand it has presented challenges meeting pollution control standards here in the US. That's why cars in many other countries are getting significantly better MPG than similar models here. And cars like the new Fiats have to be de-tuned for import so they meet US emissions, but it leaves them less than impressive on MPG numbers. Being an autocycle the Elio has a different standard to meet, so that may be where some of it's improvement comes from.
Also, it's not an 'engine' technology, but removing 1 wheel reduces rolling resistance, the reduced cross-sectional area REALLY impacts aerodynamic drag, and weight is always a HUGE factor. So maybe restricting the question to 'engine only' misses many other pieces involved.

 

[Music Man]

And it's exhaust is methane. PU.

View attachment 3080

Time to feed the cat again!

 

[ecdriver711]

I personally question the decision to use a chain rather than a belt. Chains last longer and are noisy. Belts are quieter but need to be replaced at 100,000 or so. For me replacing a timing belt is no big deal. If I had to pay someone to do THAT would be a big deal. My old Caddy has 4 camshafts, 3 timing chains and 245,000 miles and appears to be all original so the chains really do last.

I would have to pay for a timing belt change, so I like the chain. In my small world I saw a chain fail once. A classmate in collage had a really high milage raged mustang and turned if off once and it would not start again-chain broke.

 

[ecdriver711]

Reliable numbers shows around .82% at best.
So about 2/3 of a single MPG, on an Elio (assuming 84mpg)
Not worth it. Keep that .66mpg. I'll keep reliability.

They said depending on the mass of the vehicle. So probably less then .5mpg loss. Unfortunately, I drive enough to wear out a lot of cars and have had to replace many belts. Money out of my pocket.

 

[karl]

I have replaced a lot of timing chains in my life. Belts have become far more robust than the first ones. As usual perception has not kept pace with change.

 

[Brainmatter]

I agree ! its neglible at best.
service Iintervals outweigh any gain here.

The high stresses placed on timing chains by direct injection is increasing service intervals. Most direct injection systems require additional fuel pumps capable of producing very high pressures in order for the injectors to 'work' (I say 'work' to keep it simple). These pumps are often directly or indirectly driven by the timing system, and in cases where a chain is used, it is wearing timing components out. http://www.pceo.com/node/262
It is interesting to note that on Fords most efficient engine using direct injection, the 1.0L ecoboost, they use a timing belt. This timing belt was specially developed and lives in oil, just like a timing chain. It has a service interval of 150,000 miles. Best of both worlds if you ask me.

As to the original question, my opinion is metallurgy. I expect this engine to run a fairly high temperature for an all aluminum engine, say around 220 degrees? Speaking from here on in very general terms; This was not possible years ago.
The higher temps you can run an engine at, the more efficient it becomes. Thermal efficiency is the term. The holy grail of engine design has been the all ceramic engine, because ceramic is stable at very high temperatures. Anyone can guess why ceramic is not so great in many other ways. But anyway, the newest components and aluminum alloys can withstand some pretty high temps while remaining essentially the same dimensions. This allows the engine to safely run a more lean a/f mixture, run hotter, still seal all combusion gasses in the cylinder and etc. etc. But anyway, way more efficient, and all because modern metallurgy makes it all possible.
And if not, say they keep temps at 180<deg> or so, we have ourselves a pretty basic engine with cheap(er) aluminum alloy. But that's not so bad in a low load application anyway.

 

[Brainmatter]

Higher compression = better efficiency, but as I understand it has presented challenges meeting pollution control standards here in the US. That's why cars in many other countries are getting significantly better MPG than similar models here. And cars like the new Fiats have to be de-tuned for import so they meet US emissions, but it leaves them less than impressive on MPG numbers. Being an autocycle the Elio has a different standard to meet, so that may be where some of it's improvement comes from.
Also, it's not an 'engine' technology, but removing 1 wheel reduces rolling resistance, the reduced cross-sectional area REALLY impacts aerodynamic drag, and weight is always a HUGE factor. So maybe restricting the question to 'engine only' misses many other pieces involved.

The specific pollutant is Nitrogen Oxide. High compression engines (again, in general) produce more Nitrogen Oxide emmissions than low compression engines. It takes high temps to produce NOx and High compression raises combustion chamber temps where the NOx are produced.

The European standards for NOx emmissions is much lower than it is in the states. This is why Diesel engines were allowed to become popular in Europe. Diesels were essentially mandated out of existence here due to NOx regulations. Now, modern after treatments and filters are effective at controlling NOx. As these become cheaper and less onerous for car owners (unlike urea injection systems) we'll start to see more diesels.

 

[TeamCoconutOreo]

If the Elio's powerplant will use a high compression, I wonder how much it would benifit from an air fuel mixture and or timing curve tuned for 91 octane gasoline? Would the difference in engine efficency help offset some of the higher gas cost? Would it make a noticible difference by the most important meter, the seat of the pants meter?

I'm sure someone will do it and I'm curious to see the results.

 

[harlan stephens]

Being this motor is being tuned for max mpg. Bet a performance style tune and more octane will put up more hp/trq .
I for one would be happy with say 50 mpg and a little more oopf.

A power adder would be fun turbo or supercharger. If the motor can handle it.
Rotating assembly ..rods ect.

Never could keep a car or bike stock for very long

 

[bowers baldwin]

Now that I am a Fiat owner, I have to chime in with their MultiAir engine technology.

neat stuff, but I am now WAY out of my league as far as servicing this engine myself.