Comments on: EcoMotors OPOC Two Stroke Engines – Opposed Piston Opposed Cylinder

By: Douglas

Douglas — Fri, 11 Feb 2011 06:27:34 +0000

Is there anything new as of February 2011 on this engine?

By: kim

kim — Mon, 26 Jul 2010 11:53:13 +0000

Eric; The pic of the opposed piston version was probably only to make it easier to see how the concept works. The was no info in the article about its origins.

By: Eric Jameson

Eric Jameson — Mon, 26 Jul 2010 02:54:16 +0000

I am slightly confused – is the black-and-white picture immediately above the picture of the old NSU bike the old NSU’s engine or the OPOC engine? It appears identical to the OPOC engine.

By: Eric

Eric — Wed, 09 Jun 2010 17:31:47 +0000

I didn’t read all the comments, but this is a diesel engine. No oil fuel mixing. It’s also very simple. Far fewer moving parts than a 4 stroke engine. Crank, 6 rods, 4 pistons, blower. Probably some gear drive assembly out back for water pump, oil etc. This example is turbocharged also, but that is not necessary for operation. The parts in this design are just larger.

Compare to a 4 stroke engine. valves, cams, rockers or cam followers, something to drive the cams, etc.

The older detroit diesel 2 strokes engines have similar intake ports in the bottoms of the cylinder walls but with conventional exhaust valves. The DD 451 had a second set of ports in the cylinder wall for exhaust. It was an extremely smooth engine. Still had a cam to operate the fuel injectors.

By: Peter

Peter — Thu, 25 Mar 2010 20:52:53 +0000

This would make a good aero engine and opposed piston designs have a long history.
The German Jumo designs of the 1930s had 10s of thousands of flight hours, used in JU88 bombers and transports in WW11. Development stopped when Turbo prop engines came along. At the moment there are two small opposed piston 100hp aero diesels in development a 2 cyl 4 piston and a 3 cyl 6 piston, both geared twin crank shaft designs like the Jumo. There are other 2 stroke aero diesels in development a 300hp 8 cyl 2 row radial which has about 1lb/hp a 200hp 4 cyl V4, a 120hp 3cyl inverted 2 stroke with poppet valve.

All these designs have both a super & turbo charger to overcome the low rev problems with turbos. So one of the secret of this design is the electrically driven turbo. Which is copied from an idea from a Continental Aero engines design in the 1990s a 2 stroke design.
This design being a 2 stroke it is like putting a 2 to 1 gearbox on a 4 and with the
opposed pistons that is another 2 to 1 so 2000rpm is like a 4 at 8000rpm.

Full power at such low revs is good on aero engines, as turning a prop over greater than 2700rpm gives problems, with prop tips going supersonic. The only problem is with the 325hp 2 cyl design, very large torque pulses, with the prop driving the engine 30% of the time, can give dangerous resonances, not good for prop life.
On this design 4 cyl are a minimum, this would always give positive torque pulses and lower torque ripple per rev.

For a diesel bike this would give the BMW boxer formate with good power output.