Hi Efficiency Engine Design

2/21/2002 | John Jamieson

[John Jamieson]

Hi Efficiency Engine Design
John Jamieson MIT67

I’ve been studying the reasons that modern internal combustion engines operate at 25 to 30% efficiency for the last year or so. There are basically three main areas that seem repairable but would lead to large efficiency increases.

1. Current engines are symmetrical stroke. They have the same compression ratio as exhaust ratio. About 10 to 1 is the limit for compression ratio with modern gasolines, but the ideal expansion ratio is more like 25 to 1. Atkinson realized this problem in 1896 and patented and built many engines to prove the concept. He was run over by lighter, smaller, cheaper Otto cycle engines. (Current “Atkinson cycle” engines are really “Miller cycle” engines, without asymmetrical strokes).

2. Current engines cannot adapt to variable displacement to adjust output. High output can very efficient but low output requires throttling of the air, reducing compression ratio and efficiency. (Most cars only require 10 to 20 horsepower to cruise at 60 mph).

3. Current engines generate about half their internal friction due to piston side loads. Several patents claim to correct this but most are statically indeterminate, which means they don’t work.

Come up with a new engine design that fixes these three problems and you’ll improve IC engine efficiency by 50 to 100%.

Please don’t tell me about any existing technology, I’m familiar with the vast majority of existing designs, having studied over a thousand patents. Most don’t close to solving these three problems in any practical way. Original ideas only please. Yes, I do have a design that solves two of the three problems, that I’d be glad to share with anyone interested. (Graphical simulation in VB available).

[lewislynn]

There was a WWII radial aircraft engine where the cylinders rotated around a fixed shaft.

[Logophile]

At what temperature are you planning to run your new engine?

[John Jamieson]

You always have all the friction of the big engine plus pumping loses. GM is going to try it again, I understand.

I built at two cylinder out of a 4 cyclinder Opel in the 70's. Top speed 55, but mpg went from 30 to 40. Research shows about 3% efficiency increase per 10% displacement decrease.

[techcor]

Ok, I have what you want but you'll have to take a couple of minutes and check it out. There is an article from Popular Mechanics (www.popularmechanics.com) in June 1998 by Jim Wilson about an invention by Dr. Claudio Filippone that can extract more energy from the processing of nuclear waste than ever before. The device mostly is a piston engine with a special heat cavity (I believe it is a super-caviation chamber).
Now this special chamber in the piston can take the thermal efficiency of the reactions up to 56% whereas normally it is around 30%. Now I know you didn't ask about nukes so here's the final part of the article:

Although the Department of Energy has expressed interest in funding more research, Filippone is realistic about NPTRE's prospects. However, he believes that even if no NPTRE is ever built, the research that went into the project will produce dividends. The heart of the system–the intricate heat cavity that flashes water into steam–can coax higher efficiency from any type of heat engine. Including those that just putter along, cutting grass.

[John Jamieson]

Cars that must be driven 500,000 miles to recover their added cost.

The $5,000 battery replacements ever 100,000 miles are going to eat up additional savings (and cause law suites).

Braking energy is very low in a properly driven car. Do your brakes run real hot?

[Southack]

Magnetic cylinder walls and opposing piston walls could create something near-frictionless ala MAG-TRAIN style levitation, too...

[John Jamieson]

Worked very well. It was a great idea and I do think that it might have automotive applications. Extends the exhaust expansion ratio nicely. Excellant point.

[John Jamieson]

Same as now, but exhaust will be cooler. Might cause a problem in the catalyst

[Magician]

A single cylinder, two cycle (low friction, few moving parts), turbocompound (uses exhaust energy), turbocharged Diesel (ideal 25:1 compression ratio).

[blabs]

If you're looking for fuel effiency, forget it. This is controlled so that our consumption of gasoline continues to fund the oil money pool. Devices have been created, even in the early 1900's, that were put on a carburator, that provided over 200 miles to a gallon of gas.

where is it now, you ask? Buried in the vaults of the oil co's. Where's the inventor? Dead of course..

[NilesJo]

Can you send as a DWG or DXF file? If not send VB and I'll find someone with the software. Thanks.

[rebelskid]

bingo....found it.. http://www.cci-29palms.com/jocko/html/powerring.html

[_Jim]

What studies have you done in so far as the contribution heat loss (heat loss into the head, cylinder walls and pistom head) in the engine has (this 'heat loss' REDUCES ths power available during the power stroke by reduing the peak pressure seen just after ignition)?

Of course, to solve that problem falls into the category of changing the coeficient of heat transfer in the materials used - and that may be out of reach for all except those with BIG BUDGETS for doing research in exotic materials (like low heat-loss/tranfer ceramics, etc.).

Looking for 'incremental improvements' in current designs I'm sure is something all the major engine designers have done ...

[damnlimey]

Did you check out the Beare 6 stroke Ducati

It addresses some of your problems.

[John Jamieson]

A piston controlled by linear motor/ generator could control piston movement very well and do all three things, but what's the efficiency of the electric part. You end up with a high efficiency generator for electric cars!??? I like it!

[John Jamieson]

Its executable, less than 100k, I think.

[John Jamieson]

You need VBRUN but that comes with windows.

[_Jim]

Cars that must be driven 500,000 miles to recover their added cost.

Your 'costs' are for what - the current costs of OE materials and replacement batteries and fuel?

With improved manufacturing methods those costs can plummet ...

Any predictions on where the cost of fuel will go?

[mamelukesabre]

The math on that problem is pretty simple: one big piston (ala Steam engine size) has less side load friction than a bunch of smaller pistons because it has less side load area.

~~~~~~~~~~~~~~~~~

Yep. Then on top of that, you can use a really really long connecting rod. The reduced angle betweent the rod and the cylinder wall greatly reduces the horizontal component of the force.......Thus side load is further reduced

[Poincare]

Standard IC engines in are of low efficiency because they need to work at a variety of speeds and loads. Engines that run generators can run at a constant speed and thus can have valve timing and profiling, etc., optimized to that specified speed and load.

The IC engine in a hybrid car can be quite efficient, more than enough so to make up for the loss of efficiency of the generator and electric drive motor(s). The gas-electric hybrid was invented early in the last century by Ferdinand Porsche and was the principle behind the diesel locomotive. Hybrid vehicles have the advantage of good pick up due to the good torque found in electric motors. They should catch on.