Opposed Piston Diesel Engine: Difference between revisions

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A different approach: http://www.gizmag.com/duke-engines-axial/33631/ or this: https://www.youtube.com/watch?v=aZB0Go3Kj-k
A different approach: http://www.gizmag.com/duke-engines-axial/33631/ or this: https://www.youtube.com/watch?v=aZB0Go3Kj-k
== Goals ==
== Goals ==
The goal of the engine is to simplify design. With a focus on fewer parts and easier to fix. Because of CNC manufacturing, the solid parts can be complex and precise, so long as replacing them is simple.
The goal of the engine is to simplify design. With a focus on fewer parts and easier to fix. Because of CNC manufacturing, the solid parts can be complex and precise, so long as replacing them is simple.
This is interesting, and simple: https://www.youtube.com/watch?v=OwL7gApJhjw


== Pistons ==
== Pistons ==
The pistons are opposed in a single chamber. I'd like to see if the pistons can be machined with enough precision to not need rings.
The pistons are opposed in a single chamber. The pistons are ringed in permanent magnets, rare Earth. I'll probably make the core out of steel to help with the magnetic field. To be lighter, the pistons should sort of cup shaped.
 
Even further in the half baked ideas would be to intentionally leave a very small gap (sub millimeter) to reduce friction. The pistons could be aligned either with air pressure or magnetism (particularly induction).
 
== Timing Profile ==
I drew out the timing profile, and I think it's possible, though it's interesting.


The piston chamber has a opening at either end for intake and outlet, but no valves. There is a fuel injector closer to the intake side. P1 is the piston on the intake side and P2 is on the outlet side. Position I is the outside edge of the inlet, C is the center (and the point of combustion) and O is the far side of the outlet.
I'd like to see if the pistons can be machined with enough precision to not need rings. A v2 improvement would be looking at ways to reduce friction with something like fluid bearings.


I think the piston cams will be wedged between two camshafts - one to push and one to pull.
== Cylinder ==
The outside of the cylinder will be steel pipe. I'll make an inner core of wound enable copper wire, with several stages (I'd guess 6). The inner layer will be smoothed with high temperature epoxy. I think the best approach is to make a wax cylinder the exact size of the piston, and then melt it out after the epoxy has set.


=== Intake and Combustion===
== Valves and Air Flow ==
Intake begins with the pistons touching. P2 is driven by a cam linearly from I to C. When P2 is halfway through this motion, P1 beings moving, also linearly, but at twice the speed. The result being that P1 and P2 begin with no gap under the intake, a gap opens up, then closes towards the center. The fuel injector is timed to fire just after P1 closes the intake. The pistons come close enough to compress the air and begin diesel combustion.
There are 3 air states; high pressure (HP), atmosphere out (AO) and atmosphere in (AI). Fuel is injected at a constant, but adjustable rate to atmosphere in.


The compression ration needs to be about 25:1.
There are two valves, one inside (I) the pistons, with the two outer (O) sections connected together to a single valve.  


It may also make sense to put the fuel injector just outside the intake and fire it just as P2 begins to move.
This gives us 9 states, but I'm not sure how many are actually used:
# I:HP/O:HP
# I:HP/O:AO
# I:HP/O:AI
# I:AO/O:HP
# I:AO/O:AO
# I:AO/O:AI
# I:AI/O:HP
# I:AI/O:AO
# I:AI/O:AI


=== Expansion ===
== Combustion Operation ==
At this point rather than the cam driving the pistons, the pistons switch over to deliver power. So the

Revision as of 20:21, 27 April 2016

Half-baked idea.

I've been looking at Opposed-piston_engines and I'm interested in them, particularly the M4+2. I really like this one and this too. This is my try at designing one.

A different approach: http://www.gizmag.com/duke-engines-axial/33631/ or this: https://www.youtube.com/watch?v=aZB0Go3Kj-k

Goals

The goal of the engine is to simplify design. With a focus on fewer parts and easier to fix. Because of CNC manufacturing, the solid parts can be complex and precise, so long as replacing them is simple.

Pistons

The pistons are opposed in a single chamber. The pistons are ringed in permanent magnets, rare Earth. I'll probably make the core out of steel to help with the magnetic field. To be lighter, the pistons should sort of cup shaped.

I'd like to see if the pistons can be machined with enough precision to not need rings. A v2 improvement would be looking at ways to reduce friction with something like fluid bearings.

Cylinder

The outside of the cylinder will be steel pipe. I'll make an inner core of wound enable copper wire, with several stages (I'd guess 6). The inner layer will be smoothed with high temperature epoxy. I think the best approach is to make a wax cylinder the exact size of the piston, and then melt it out after the epoxy has set.

Valves and Air Flow

There are 3 air states; high pressure (HP), atmosphere out (AO) and atmosphere in (AI). Fuel is injected at a constant, but adjustable rate to atmosphere in.

There are two valves, one inside (I) the pistons, with the two outer (O) sections connected together to a single valve.

This gives us 9 states, but I'm not sure how many are actually used:

  1. I:HP/O:HP
  2. I:HP/O:AO
  3. I:HP/O:AI
  4. I:AO/O:HP
  5. I:AO/O:AO
  6. I:AO/O:AI
  7. I:AI/O:HP
  8. I:AI/O:AO
  9. I:AI/O:AI

Combustion Operation

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