Ways to increase diesel engine efficiency?

[manousos]

Originally Posted by GreenHornet

. . . the (OPRE) Opposed Piston Pulling Rod Engine, (PatOP) Single Crankshaft Opposed piston Engine, and (PatPOC) Single Crankshaft Opposed piston Engine of different design. These engines can be considered offspring of the Junkers Doxford engine. These are opposed piston engines that are direct injected with diesel. With some modification they can also be spark ignited gas guzzlers! These engines spend more time at BDC and increase piston dwell to increase engine efficiency among other improvements. They have far less parts as well as far less moving parts then a conventional diesel today. They are far lighter and much more compact in design. They can literally fit under the seat of your car how is that for packaging.
GH..

Thanks GreenHornet.

A "correction": the pistons of the OPRE and of the PatOP (in both designs the connecting rods are pulling rods in the meaning that the high pressure into the combustion chamber loads the connecting rods in tension) do spend more time (some 35%) in the "combustion TDC", but the pistons of the PatPOC design spend in the combustion TDC as much time as the conventional (push-rod) engines.

The full balance is another characteristic of these engines.

When the single cylinder OPRE drives a divided load, like two counter-rotating propellers, as in the Portable Flyer,



the basis of the engine is perfectly rid of inertia vibrations (forces, moments and torques) just like a Wankel rotary and a V12 conventional; the basis of the OPRE engine is also perfectly rid of combustion vibrations (not possible in the case of the Wankel rotary and of the conventional V12 wherein the engine basis has to provide a reaction torque each time an expansion takes place). See the video at the bottom of the Portable Flyer section of the pattakon.com web site and think what it means for a lightweight Portable Flyer.


A characteristic / advantage of the (single) crankshaft PatOP (and PatPOC) is that the main bearings of the crankshaft are rid of loads. Theoretically you can keep the crankshaft by your hands during operation.


"With some modification they can also be spark ignited gas guzzlers!"

Like the spark ignition OPRE with the tilting valves (animations at the tilting valve section of the pattakon.com web site).





Think about the rev limit and the power density.

Thanks
Manolis Pattakos

[GreenHornet]

"A characteristic / advantage of the (single) crankshaft PatOP (and PatPOC) is that the main bearings of the crankshaft are rid of loads. Theoretically you can keep the crankshaft by your hands during operation."

With the single crankshaft I believe this would also reduce friction and increase efficiency over conventional designs.

"Think about the rev limit and the power density."

Rev limit would be far higher and power density enhanced compared to current conventional designs.

These are both very desired enhancements to our current engine technology in our cars and other modes of transportation today. They pave the way for decreased engine sizing for reduced emissions while maintaining accepted power output of the modern vehicle.

Thanks for the great input and animation of your designs Manousos

I look forward to more of your posts and input in this important thread,

GH

[Diesel_Dave]

Forgive me if someone already posted it, but here's a paper that explains more techincal details of the original concept:
http://web.mit.edu/shkolnik/www/asmepaper/LP_ICEF.pdf

[Jasen]

I ran across this a few years ago on pre vaporizing fuel. Interesting read

Tom Ogle ~ Vapor Fuel System

[oil pan 4]

If prevaporization of fuel works so well then why don't propane engines offer a substantial increase in fuel economy over gas engines on a BTU/mile basis?

[RustyLugNut]

Originally Posted by oil pan 4

If prevaporization of fuel works so well then why don't propane engines offer a substantial increase in fuel economy over gas engines on a BTU/mile basis?

Here is a masters level thesis on simulated engine performance with comparison to test data.

http://repository.tamu.edu/bitstream...EEN-Pathak.pdf

The brake specific fuel consumption (BSFC) is only 3-5% better than the gasoline analog (iso-octane). Thus, it can be concluded that a gas state engine has only a small advantage over liquid state engine.

However, this does not take into account the change in other variable conditions that gasoline evaporation systems add to the combustion environment. People make reference to the old "evaporator carbs" and claim huge mileage increases. I have constructed "vapor carbs" in the past and measured only a 50% improvement in fuel economy at cruise on older carburated truck engines. A modern application on modern engines yields a 30% efficiency increase. Here is a link to a legitimate company effort.

Vapor Fuel Technologies | Home to the VFT Vapor System

[Awd180]

bump

[redpoint5]

Found an article on TTAC today on this engine.

[cRiPpLe_rOoStEr]

Opposed-piston 2-stroke Diesel engines seem to be a reasonable option. Older ones such as the Rootes/Lister TS3 which was fitted to Commer trucks actually had overall cleaner emissions than many Euro-3 rated vehicles with similar capacity, being disfavored only when it comes to PM emissions for which the modern electronic management provides a more accurate control.

[redpoint5]

How does the exhaust evacuate the cylinder at the same time that fresh air is drawn in? I don't get 2-strokes.