Public Domain Hi-Eff Engine Design DIY

4/28/2003 | John Jamieson

[John Jamieson]

Please help me get the word around to those in the automotive biz or other interested parties.

Comments welcome.

John

[martin_fierro]

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[Orbiting_Rosie's_Head]

Interesting Idea. A 5-stroke 2-cylinder engine from a regular 4-cylinder, 4-stroke engine. But why the high cost to develop and test? Sounds like an operation that a friend of mine who use to build motorcycle racing engines could do in his well-equipped garage.

[John Jamieson]

Sounds like engine Guys and Gals, thanks.

John

[John Jamieson]

That's if the big boys do it. You and I could do it for peanuts. GM spent $1,000,000,000 on the Impact..... and then crushed 'em.

[bmwcyle]

bttt

[The_Victor]

Cool concept.

I would have thought the exhaust pressure would have been too low for a second expansion cycle. Obviously you have made the calculation do demonstrate otherwise.

Is the fuel efficiency calculation just an extrapolation based upon the effective expansion ratio?

[alloysteel]

OK, some of my latent engineering insight kicks in. Rather than using the two middle cylinders of a four-cylinder IC block, build a single double-acting piston, tied into the crank, using the exhaust portion of the cycle from one cylinder to drive the piston down, and the exhaust portion of the cycle of the other cylinder to drive the piston up. This scavenges a lot of the remaining energy in the exhaust stream, and gives up a lot of heat in the process. Thermal efficiency should be much improved. And rather than poppet valves, use slide or rotary valves, to reduce internal inertial resistance to opening and closing the various valves.

If you identify this as an adaptation of an external combustion engine using steam as a medium, that is correct. The engineering is about 80 years old, going back to the time of a fellow named Abner Doble. With a really good water vapor reclamation system, condenser and heat exchanger tank, the system was superior to any internal combustion engine of the time, and would be on a par with the most advanced engineering of an internal combustion engine of today. With minimal emissions.

[Consort]

How much will one of those effing engines cost?

[Jack of all Trades]

A full authority electronic valvetrain opens up a world of possibilties. How do you think the efficiency of your idea for increasing expansion compares to cylinder deactivation? With Sturman valves, you could do either or both.

I think you'd better add another zero to your proposed development cost. Sturman will want your million just to design the valve and build a few protoypes. Then you'll still have to D&B the cylinder head and engine control system. Then you'll need a dyno with emissions capability. At that point you'll be ready to start engine development.

Bosch, Delphi and a few others have deep pockets and buildings full of PHd's working on future IC engine configurations. If they are not working on this concept, why do you think that is? If they are working on it, how do you propose to compete?

[boris]

"3. The author experimented with 2-cylinder engines based on a 4-cylinder 1.9 liter Opel in the 1970’s. This car demonstrated about a 40% increase in fuel economy, but suffered poor horsepower performance, barely reaching the 55mph top speed of the day. Never the less, the car was driven to the Kennedy Space Center every day for over a year. About 2 years ago, the author started wondering if the two extra cylinders could be used for additional gas expansion, and the present idea was born. A 1987 Toyota Corolla was purchased and the conversion began, only to be never completed because of a combination of health issues, and more pressing time demands. "

My professor (mechanical engineering) at Cornell in 1971 experimented with this notion. He had a V-8 running on 6 cylinders and two as 'expanders'. I would not be surprised if he had a patent or two. My 51-year-old brain is refusing to give up his name but eventually it might.

--Boris

[boris]

High-compression ratio engines have been known to be good for a long time. The government basically outlawed them because of pollution concerns. If you look at a curve of Nox emissions versus compression ratios you will see what I mean. The "Muscle Cars" of the 60's and early 70s ran at much higher compression ratios than do today's engines because there were no Nox emission standards.

Nobody had heard of catalytic converters, and the notion of an engine that would not start unless its computer was working right would have been thought insane.

--Boris

[boris]

Ah HA! His last name was Booker. That was the prof's name. I'm still working on his first name.

[John Jamieson]

Yes, more area under the curve.

[Jack of all Trades]

The current model Acura RSX has a 2.0 liter 4 cylinder engine with an 11.0:1 compression ratio. Valve and ignition timing control along with combustion chamber design keep the engine from melting. EGR is used for Nox reduction. A 10:1 CR engine that runs on 87 octane gasoline is a common thing today.

[John Jamieson]

A lot less than a diesel upgrade ($1400) which pays off in 60k miles. And much less than hybrid ($5000) which never pays off.

Depends on the valve train costs, I would guess $200 to $600 extra. Payoff in 30k miles or so.

[John Jamieson]

You get both cylinder deactivation and exhaust expansion with this idea, no trade off needed.

The big boys keep their research secret.

[John Jamieson]

He was on the right track.

[John Jamieson]

This is not a high compression engine, just high expansion.

[boris]

"This is not a high compression engine, just high expansion."

Hey, I'm just a rocket engineer. In rockets you can 'overexpand', i.e., allow the exit static pressure to drop below ambient.

How do you do that in a car? A high expansion ratio kind of implies a high compression ratio, or am I missing something?

--Boris