8/27/2014 Tech Talk - More On The Elio Engine

[zelio]

Elio Motors Tech Talk v31
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Elio 3 Cylinder Cooling System

One of the key areas of focus for the engine design is the cooling system. This system includes the water jacket around the cylinder chambers and the cylinder head, the cylinder head gasket and the water pump. Significant analysis and design has gone into the Elio engine.

Water Jacket
When designing the water jacket, the focus was to maximize the cooling potential in terms of maximum flow velocity, maximum velocity distribution, minimum volume, and minimum metal temperature. The design was then analyzed using modern Computational Fluid Dynamic (CFD) software to optimize the prototype layout.

Image 1: CFD of the Elio Crankcase Water Jacket

The cylinder head portion of the water jacket was designed with the intent of maximum combustion chamber cooling; reducing the required octane content in the fuel used which in turn allowed for higher compression ratios. The volume was kept to a minimum to keep flow velocity as high as possible. A connecting bridge was also added along the “spine” of the water jacket which had the benefits of increasing cross-cylinder flow velocity as well as eliminating air pockets that would accumulate between the cylinders. Detail was also taken to extend and loop the water passages around important cylinder head features like the intake port, the exhaust port and the spark plug, thus maximizing the cooling area.

Cylinder Head Gasket
Size, shape, and the location of the orifices in the gasket were tuned to optimize flow from the cylinder into the head sections of the water jacket. The orifices around cylinder one were made larger to encourage additional flow into the head at cylinder one, with smaller orifices around cylinders two and three to keep flow velocity high and uniform. The design allows most of the water to come up at cylinder one, then travel across the top of the cylinders to the outlet, instead of flowing the water up and over one cylinder at a time.

Image 2: Elio Cylinder Head Gasket

Water Pump
The water pump was designed to be more efficient by using curved vane impellers, and to operate at a lower flow rate, resulting in a water pump which is slower with reduced parasitic properties. The water pump is mounted off to the bulkhead side, with the water jacket intake coming in on the side of the engine instead of on the front cover. This was done to keep the water from the water pump separate from the oil in the wet front cover in the event of a water pump failure. Pressure relief holes are drilled into the impeller base to relieve the negative back pressure between the impeller and seal caused by the impeller rotation. This preserves both seal integrity and flow uniformity. A small chamfer is added on the leading edge of the impeller blades to reduce flow separation, therefore reducing cavitation.

Image 3: Elio Water Pump

With all of the design and analysis that has gone into the cooling system, the Elio engine will remain at optimal operational temperature with a minimal effort.

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[Keith Stone]

Glad they are making progress, but I can't hardly wait until elio produces a running engine! This suspense is killing meo_O.

 

[PJ]

Glad they are making progress, but I can't hardly wait until elio produces a running engine! This suspense is killing meo_O.

I do hope it last's

 

[Jim H]

Glad they are making progress, but I can't hardly wait until elio produces a running engine! This suspense is killing meo_O.

We all want to hear Elio say "drivers start your engines".

 

[Terrence]

Thanks Zelio (oregon) for quick posting here in elioowners.com the just released tech talk v31! There is an awesome amount of detailed information about the Elio cooling system they released on the cooling system! Just Awesome; the engineering, R & D, tooling! Superb job they are doing to our Elio! Thank you Team Elio & Paul Elio for quality, reliability and 84 mpg!! HOORAH ! Paul Elio had said this is a special motor being designed for the Elio to get 84 mpg , which he will sell for $6,800.00.. Such a brilliant-innovative team Paul Elio put together!
Terrence

 

[CheeseheadEarl]

It's interesting to me how small the cooling passages are.

Far different than what is in a big old cast iron V8, for a couple reasons. First is the rate of heat transfer is much higher with aluminum, and second (learned this here) is that the compact design of a 3 cyl has a lot of surface area per cylinder and that can make retaining enough heat for efficient operation difficult.

None of that bothers me, but the small passages mean a neglected cooling system will cause trouble sooner. Fairly regular flush and fills will go a long way toward long engine life.

 

[Smitty901]

Modern day coolants have done away with issues such as green goo and scale that clogged cooling system. So I am not to concerned. The only time it would become an issue is if you added water or cheap stuff to it and failed to drain it and refill it correctly . Last month we look at a Cat engine that is 20 years and had been used and abuse the whole time , it looked almost new inside. It was changed over to life time coolant back when it was still almost new.
Passages in cooler in our heavy equipment are very small , with modern coolants we do not touch the system for 6 years now.
My only concern with a new engine is wear surfaces it seems that almost every new engine design has some kind of bearing wear issue some where at first. That happen to Victory the their new engine even after years of design and build.

 

[wheaters]

The relatively high velocity coolant flow through smaller sized passages should help prevent scale and sludge build up.

 

[Terrence]

Modern day coolants have done away with issues such as green goo and scale that clogged cooling system. So I am not to concerned. The only time it would become an issue is if you added water or cheap stuff to it and failed to drain it and refill it correctly . Last month we look at a Cat engine that is 20 years and had been used and abuse the whole time , it looked almost new inside. It was changed over to life time coolant back when it was still almost new.
Passages in cooler in our heavy equipment are very small , with modern coolants we do not touch the system for 6 years now.
My only concern with a new engine is wear surfaces it seems that almost every new engine design has some kind of bearing wear issue some where at first. That happen to Victory the their new engine even after years of design and build.

There is also the radiator to tie into the motor for cooling the heated coolant, electric fans attached to radiator, placement of radiator and as you mentiond the ever improving coolant. Lots of research, engineering, testing, documentation, evaluation, meetings/reviewing/approval with every segment of our Elio.
Terrence

 

[goofyone]

....Lots of research, engineering, testing, documentation, evaluation, meetings/reviewing/approval with every segment of our Elio...

All this work is exactly what separates Elio Motors from many other low volume vehicles and/or kits.

It is very true that anyone with the proper skills can build a similar vehicle on their own or offer a kit and/or low volume vehicle however the issue with these vehicles is that they are generally sold with little to no testing and generally after only a few prototypes have been built to make sure everything goes together ok. These vehicles can be a lot of fun however they are also more expensive as they don't benefit from the economies of scale inherent to mass production and the quality and longevity of the vehicle is very much in question as they often require a lot of work over time to keep operational. These vehicles also rarely benefit from advanced safety systems such as airbags and stability control systems.

The reality is that it takes a lot of effort, time, and money, to bring to market a properly engineered and tested high volume production vehicle which is designed to last with the minimum of maintenance and provides such amenities as advanced safety systems all while keeping the price as affordable as possible.