4 replies to this topic

[manolis]

Hello.

With the Search and Examination Report from the UK-IPO (United Kingdom Intellectual Property Office) received, here:



and here:



is a turbocharged 2-stroke PatAT (Asymmetric Transfer) direct injection Diesel design.


The exhaust gas, by means of a turbocharger, powers the scavenging.

With the exhaust closing before the transfer, the gas pushed into the cylinder has no way to escape (more or less as in the Opposed Piston - say Junkers Jumo - supercharged or turbocharged 2-stroke Diesels).




The lubrication of the crankcase is true 4-stroke (compressed lubricant feeds the plain bearings, splash lubrication of the lower piston skirt - cylinder liner, oil scraper ring, recirculation of the lubricant).

The oil ring never passes over cylinder ports.

At the TDC the oil ring abuts and lubricates the cylinder liner area just below the ports. Then it scraps the surplus of lubricant from the cylinder liner back to the crankcase (from wherein, after it is cooled and cleaned, it feeds the oil pump again).

At the BDC the lower compression ring (or both compression rings, depending on the design) abuts on the abovementioned area of the cylinder liner moving over the lubricant film left by the oil ring 180 crankshaft degrees earlier (worth to mention: the required oil film for the lubrication of the compression rings is a few times thinner than the oil film required between the piston skirt and the cylinder liner).


How it operates?

The exhaust port is the opening at the left side of the cylinder.
There are three conventional transfer ports (the one at the right side of the cylinder).
There are two asymmetric transfer ports (passageways at the sides of the cylinder allowing the communication of the space into the cylinder with the space under the piston crown when the connecting rod permits it).

The compressed air from the turbocharger (or from a supercharger) passes - through the three transfer ports - into the cylinder and pushes the burned gas out to the exhaust.
While these three transfer ports close before the exhaust port, the two asymmetric transfer ports are already open feeding the space into the cylinder with compressed air from the space under the piston crown (which is sealed from the crankcase, and which is fed by the three abovementioned transfer ports).
The exhaust port closes, but the asymmetric transfer ports keep feeding the space into the cylinder with compressed air.
Finally the asymmetric ports close and the compression begins.


The moving parts are as many as in the simplest two-strokes.

The manufacturing and the assembly is easy (for instance: the flat surfaces on the piston wherein the extension of the connecting rod abuts, opening and closing the asymmetric transfer ports, are easy to cut).


For extreme power to weight ratio and top vibration-free quality, the Cross-Radial combines four cylinders like the above with a single crankpin (more at http://www.pattakon....ttakonPatAT.htm )


Objections?
Opinions?

Thanks
Manolis Pattakos

Edited by manolis, 10 December 2015 - 10:01.

[Greg Locock]

Well that is interesting. How do you seal the con rod valve to the inner face of the piston? Or does it not need a gas tight seal?

[manolis]

Hello Greg Locock.

A small clearance, say 0.05mm, between the con-rod valve and the inner face of the piston is all it needs.
No gas tight seal is required.

During the high-pressure period, the compression rings seal the combustion chamber the conventional way: the asymmetric transfer ports on the cylinder are below the compression rings during this high-pressure period.

After the middle stroke, with the cylinder pressure being several times lower than the peak pressure, the piston opens the asymmetric transfer ports (with the connecting rod valve being at an angle not allowing the communication of the combustion chamber with the space under the piston crown) and a few degrees later the piston opens the exhaust port.

Judging from the timing used in the Opposed Piston engines (Junkers Jumo, Fairbanks-Morse, Junkers-Doxford, Ecomotors OPOC, Achates etc), the optimum timing for the closing of the asymmetric transfer port of the PatAT turbocharged Diesel is not substantially after the closing of the exhaust port.

I.e. the timing used in the animation is “too aggressive”.

The simultaneous opening, by the piston, of the exhaust port and of the asymmetric transfer ports on the cylinder seems a reasonable choice, too.


Looked from another viewpoint:

Think how much easier is the work the con rod valve of the PatAT turbocharged Diesel has to do as compared to the PatRoVa rotary valve that seals the full cylinder pressure during the combustion:



Thanks
Manolis Pattakos

[gruntguru]

Does your patent application cover both innovations (4-stroke lubrication and assymetric timing) or just one?

[manolis]

Hello Gruntguru.

The basis (the independent claim(s)) of this patent application is the asymmetric transfer and/or asymmetric intake.
The lubrication is a detail (an option) presented in the description / drawings, and "protected" by a dependent claim.

The patent application is not yet published in the UK-IPO, however a week ago it was published in the US-PTO and is available at http://patft.uspto.gov/ (publication no: 20150345372 ).

Thanks
Manolis Pattakos