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Hi Efficiency Engine Design
2/21/2002
| John Jamieson
Posted on 02/21/2002 1:31:00 PM PST by John Jamieson
Hi Efficiency Engine Design
John Jamieson MIT67
Ive 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 dont work.
Come up with a new engine design that fixes these three problems and youll improve IC engine efficiency by 50 to 100%.
Please dont tell me about any existing technology, Im familiar with the vast majority of existing designs, having studied over a thousand patents. Most dont 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 Id be glad to share with anyone interested. (Graphical simulation in VB available).
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To: narby
"Do the "Turbo Compound" thing, like on the Lockheed Constellation airplane. Uses a turbine in the exaust to capture wasted energy and directly powers the drive shaft. This uses up the wasted expansion ratio." In automobiles, this is called a 'supercharger'. You may have heard of it.
--Boris
101
posted on
02/21/2002 4:39:17 PM PST
by
boris
To: mamelukesabre
Short skirts reduce weight but the are usually for clearance on stroker cranks with correspondingly short rods.
Old motors have wear patterns on the cylinder walls that correspond to the range of motion of the rings. That tells me which part is generating the lions share of the friction.
To: boris
A supercharger blows air using the crank to drive the blower.
A turbocharger blows air using a turbine in the exaust gas to drive the blower.
To: John Jamieson
Ultrsonic nebulization of the gasoline?
Conbine with ulrasonic nebulization of water (or EtOH, or other?)
Maybe this will "cover" or "coat" the nebulized H20 (or ? EtOH) with the gasoline increasing the surface area of the gasoline and converting (quickly) the H20 to steam.
I've thought about this for some time and wonder what you think.
To: realpatriot
Damn,we need a spel ckecker on this think!
To: boris
Turbo compound is not a super charger. The output of the turbos is geared directly to the engine output shaft.
To: Blood of Tyrants
"More efficient means more power out of a smaller package."Actually, just the opposite is the way it works. A highly efficient engine of any process tends to be very large for its power output.
The diesel engine outshines the gasoline (spark-ignited) engine every time in efficiency because of its higher compression ratio. However, it will weigh over twice as much as an equally powered SI engine.
To: realpatriot
Water injection is often used to lower cylinder head temps but does nothing to the burning of the gas.
To: John Jamieson
Okay, how 'bout ultrasonic nebulization of gasoline without the water?
To: lewislynn
There was a WWII radial aircraft engine where the cylinders rotated around a fixed shaft. LeRhone (sp?)
It was WWI.
To: nightdriver
You are only considering the efficiency of scale and not taking into account new technology. For example, a 1965 VW bug had a 1600cc engine that put out about 40 hp and got about 30-35 mpg. Yet today it is routine to get 130 hp and 35-40 mpg out of an engine of the same size.
To: blabs
The guy who came up with the Pogue carburetor (Charles Pogue), the accept-no-substitutes "original" 100 MPG carbuertor, is in a nursing home in Winnipeg, Canada.
So much for your theory.
112
posted on
02/21/2002 5:51:11 PM PST
by
Poohbah
To: Blood of Tyrants
There's certainly something to be said for computerized engine management. There are, unforutnatley, thermodynamic limits - probably the most salient being that a Carnot cycle (which cannot be built) is the upper limit on engine efficiency.
I've always thought that more effort should be put into designing a good stratified charge system. It would allow higher compression ratios by increasing the "apparent" octane rating of this miserable quality gasoline we have to use these days.
To: realpatriot
--judging by
my output, I would be forced into accepting the turbocharged dual over head dyslexic version of the spel chekker meself...,
%^(
114
posted on
02/21/2002 6:38:27 PM PST
by
zog
To: realpatriot
OK, what's nebulization?????
To: Dinsdale
Short skirts reduce weight but the are usually for clearance on stroker cranks with correspondingly short rods.
Old motors have wear patterns on the cylinder walls that correspond to the range of motion of the rings. That tells me which part is generating the lions share of the friction.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Old motors also have "out of round" cylinders and piston slap. I'm glad you brought up the wear due to rings. It is the ridge created at the top of the cylinder from this wear that breaks the rings. Not the side load on the piston.
To: nightdriver
Actually, just the opposite is the way it works. A highly efficient engine of any process tends to be very large for its power output.
The diesel engine outshines the gasoline (spark-ignited) engine every time in efficiency because of its higher compression ratio. However, it will weigh over twice as much as an equally powered SI engine.
~~~~~~~~~~~~~~~~~
I'm not sure I totally buy your theory about higher compression ratios being the reason for the higher efficiency. I think it has more to do with the fact that diesels engines operate at higher temperatures and that there is a great deal of leftover heat "recycled" to vaporize each subsequent charge of fuel.
To: boris
In automobiles, this is called a 'supercharger'. You may have heard of it.
--Boris
~~~~~~~~~~~~~~~~~~
Boris, I'm afraid you're all wet here. A supercharger on a car is just the opposite. The device he was talking about takes energy from gas flow and adds energy to a rotating shaft. The device you are talking about takes energy from a rotating shaft and "charges"(adds energy) a gas flow.
To: Dinsdale
A supercharger blows air using the crank to drive the blower.
A turbocharger blows air using a turbine in the exaust gas to drive the blower.
~~~~~~~~~~~~~~~~~~~~~~~~~
If you want to get really technical, "turbocharger" is an incorrect term. It is really a turbo-supercharger. That is what they were called when they were invented for use on airplane reciprocating engines. Therefore, a supercharger is a device that "charges" the intake, and a turbo-supercharger is a device that does the same thing, only by use of a turbine.
To: mamelukesabre
Carnot cycle math from 100+ years ago shows direct relationship between compression ratio and eff. Also desiel fuel contains more BTUs.
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