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).

[mamelukesabre]

Maybe you should take a look at the total system - - and look to recover some of the kinetic energy the vehicle has when coming to a stop (where, normally, all THAT energy is simply turned to heat in the brakes). Oh, sorry - Toyota and Honda beat you to it! (To wit, the Prius and the Insight.)

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Ford had a better idea. Check out Ford's HYDRAULIC energy recovery system.

[JMJ333]

"There comes a time in every project when you must shoot the engineers and go to production." ;)

[John Jamieson]

Clinton's 85mpg car. It will work.

[John Jamieson]

Never happened.

[toast]

You may as well switch to electric motors.

Fuel cells theoretically can be very efficient. And in few years will economically be the better choice.

[John Jamieson]

Yes, I predicted $5 a gallon by 1990, back in 1974.

[mamelukesabre]

Yes, raising engine temperature helps too, Smoky melted several Buick v6's testing the idea in the 60s. He made some of them into V2s!

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I've always wondered why they didn't put the turbo charger AFTER the catylitic converter. Isn't there alot of heat energy going right out the exaust pipe that is generated by the catylitic converter?

[RichardW]

Whatever happened to the Stirling Engine?

[Southack]

Ummm... thanks, but no... I was referring to permanent magnetic cylinder walls and a permanent magnetic outer area around the piston head.

Today's technology could easily make a near frictionless magnetic-rail piston/cylinder. That's bound to reduce waste-heat and increase power and efficency while keeping everything in the entire engine design to original specs, thus lowering development and production costs (as well as time to market).

[John Jamieson]

Break even point for Prius is $11 gallon, Honda a little less, if no battery replacement needed.

[Logophile]

Wouldn't you have to operate at 1500 K or higher to achieve 80% thermal efficiency?

[John Jamieson]

Really big a heavy for any serious Hp. They make pretty good stationary engines.

[John Jamieson]

Maximum thermal efficiency increases with compression ratio, about 72% at 20 to 1. Heat loses are always subtracted from that number.

[Uncle George]

The STERLING engine could be very benificial being it works on hot, expanding air--- Install a hundred of them in congress and have FREE unlimited power output. At least we could get SOMETHING for our tax dollars.

[zog]

--yunicks designs seem the best if you are going torquey pistons. His ideas used the heat to really mix the air fuel mixture so it could lean burn, and use it in such a way that the internal cylinder heat didn't rise necessitating materials that didn't exist at the time or were too expensive. The ford ceramic engine from several years back went the opposite way, exotic/expensive materials, extreme good tolerances, no rings in the pistons required, basically minimal lubrication required,very efficient heat dispersal without a water jacket, using fine ceramics in the block and head.

another one I liked just poofed. Forget the ceos name, compaq computer guy, his company, used a turbine engine. Had decent prototypes, then his web page got locked down, and no new info was put out.

Now I had good luck just using racing tech on a pushrod engine without really trying to build a race engine. Went to great lengths to make a tight, very well balanced engine, took my balances down below a gram on the pistons and rods with a grinder. cold shot peened rods, polished crank like beyond normal. Same basic engine later on, racked up significant power and mileage increases from making it "not sloppy". Got 2 grand more redline out of it, and it's all stuff a factory could have done, fairly easily.

Here's one for ya I thought of like 35 years ago, no valves in the traditional sense. Instead use a rolling cylinder with slots cut in it, it just spins. If you wanted to make it variable it would have to slide back and forth on it's long axis as well slightly off center of wherever your optimal spark placement point would be in the head 'area" in relation to throttle demand. The shape would be weird though, definetly not hemi, it would be anti hemi, backwards, unless there was a torus (kinda) shape involved with it, not a true cylinder all the way.

[Rattlins]

Common Fella's, you sound like a bunch of little kids trying to figure out why the world isn't flat! First, gasoline is a waste product! You get it from a refining distilation process whether you like it or not! Sure we get some by cracking, because we use so much! When it was first produced, it was dumped in the Ohio, and Allegeny Rivers to keep people from trying to burn it in their Kerosene lamps. A gallon of gas produces, 25% of it's energy in results, 33% goes into your radiator, and 33% goes out the exhaust. The other percent is lost in engine friction. The solution: An Adiabatic Turbine, Comprende'?

[John Jamieson]

Converter only takes care of last fraction of 1% of unburned fuel. Not much additional energy....but some.

[ikka]

What is your opinion on the Pogue carburetor design? What if it had been using 180proof alcohol instead of gasoline? Gasoline has too high a boiling point to easily turn it into a vapor.

[Dinsdale]

Rocket cars with very high exhast velocities.

I know the efficencys will be lower, but I want one anyhow.

[blabs]

http://www.io.com/~maniac/environ.html really..I can find more links for you if you'd like