Opposed Piston Engine OPRE

pattakon OPRE III prototype, single cylinder, 500cc engine running on Diesel fuel.
With 40% longer piston dwell at TDC.
With four-stroke like lubrication.
With built-in piston-type scavenging pumps
For more: www.pattakon.com

Category:

Autos & Vehicles

Tags:

• opposed
• piston
• engine
• pulling
• rod
• vibration-free
• dual
• crankshaft
• pattakon
• scavenging

[pattakoncom]

What kind of diesel injection pump are you using? what kind of injector?

Mechanical from a Chinese power generator set. Pump and Injector made by Ningbo Shuntian (BF170YA and KBAL59P(120). 186F.

Instead of communicating through Youtube, you can better email me: get into the pattakon web site, at Contact, wherein the e-mail for communication is.

If you want to make your own OPRE or PatOP prototype, you can ask for the "blueprints" (for free) to strart with.

[pattakoncom]

Optimum asymmetry for the Junkers engines: 11 degrees with a centrifugal narrow-band scavenging-pump. In the OPRE and PatOP engines, wherein the pistons follow a quite different motion (some 35 to 40% longer piston dwell at the combustion dead center) the optimum asymmetry is smaller (some 7 to 8 degrees); besides, the small-dead-volume volumetric scavenging pump enables operation with symmetrical timing, too. Imagine the effect of an obstacle (like a throttle) at the exhaust of the OPRE/PatOP

[pattakoncom]

OPRE ii : scavenging pump bore 86mm, combustion bore 80mm (scavenging ratio: 1.15)

OPRE iii: pump 90mm, combustion 80mm (scavenging ratio: 1.26)

PatOP : scavenging pump bore 130mm (there is one only scavenging piston at the intake side), combustion bore is 79.5mm (scavenging ratio: 1.33)

Taking the thrust loads by the skirt of the scavenging piston, the combustion piston needs not to touch the cylinder.

An immovable ring below the ports sweeps the oil from the piston skirt.

[pattakoncom]

"What is the compression ratio?"

17:1

"Have you put this engine on a dyno? "

No dyno tests, yet.

They are “proof of concept” low-budget demonstration prototypes made to show the main advantages of the OPRE and PatOP design over the state-of-the-art.

Main advantages?

Additional time for the combustion.

Crosshead architecture for "four-stroke-like" lubrication of the two stroke.

Built-in volumetric scavenging pump for wider rev range and flatter torque curve than the four stroke.

[pattakoncom]

"Would it not be better to . . . .to intake ports to increase boost pressure?"

Not necessarily.

With quite small dead volume (the one-way / reed valves are just above the crown of the scavenging piston) the scavenging pump passes a more or less constant quantity of air to the transfer pipe around the intake ports, regardless of rpm and load.

See the big volume of the transfer pipe of the PatOP, wherein for 635cc combustion capacity, the scavenging pump passes 850cc of air per cycle.

[pattakoncom]

"What is the offset between the intake and exhaust port opening/closing?"

The offset –in this prototype- is about 6 crankshaft degrees in case of symmetrical timing (the exhaust ports open and close some 64 degrees from the BDC, the intake ports open and close some 58 degrees from the BDC).

Advancing for one tooth (or two) the exhaust crankshaft, the engine runs – still smoothly - with asymmetrical timing.

In some videos at pattakon web site the OPRE engine runs with asymetrical timing

[r8wing]

How cool! Sounds like a motorcycle engine on steroids, how fast is it revving?

[phoolosopher]

What kind of diesel injection pump are you using? what kind of injector?

[phoolosopher]

By increasing the asymmetry of the pistons, can the boost pressure be increased? what is the limit of this asymmetry?

[phoolosopher]

What is the bore of the scavenging cylinder?

In the presentation you say that the piston skirt does not touch the walls of the cylinder. What prevents the oil from leaking through the intake/exhaust ports when the pistons move to TDC?