OPOC ENGINE DBV, a revolutionary invention

Romanian innovations

OPOC ENGINE DBV, a revolutionary invention

Since 1993, DBV Research has been delivering unique technical solutions with a global approach of each and every project. Besides the fact that we are renowned for our research and innovation proposals in national auctions, we have successfully participated in various conventions abroad.

Just one example would be the International Exhibition of Inventions of Geneva, where we gained notoriety by obtaining two gold medals and one silver in the 1998 edition.

Locally, we are recognized by the Ministry of Research and Development through a title which we acquired in 1995. Our portfolio covers a wide range of industries, including but not limited to automotive, transportation, nautical, agriculture, construction energy recovery and natural resources exploitation.


Technical solutions presented in this document are intellectual property of DBV Research and protected at OSIM Romania in file no. A00607/11.08.2014 and published in Official Bulletin of Industrial Property no. 4/2015 Romania, called “Opposed-piston engines”. The references from this description are made based on notaries and attached drawings. Kinematics and additional information you can find on our site: http://opoc-engine-dbv.com/.

Why OPOC Engine

The concept of an OPOC engine has gained attention from researchers because:

  • It promises a specific power that is four times greater than an equivalent size engine.

This results from the double frequency of power stroke.

  • The concept is also simple from a constructive point of view, by eliminating the cylinder heads and the entire distribution mechanism.

Current stage

OPOC engine is well known and it has multiple versions. In the evolution of this engine, the most important step was made by Prof. Peter Hofbauer and his team at ECO MOTOR. He linked the connecting-rod of inner piston and connectingrod of outer piston with one crankshaft. The forked connecting rod is assembled to the crankshaft by means of two crankpins placed on the left and right of the crankpin corresponding to the inner piston.


Current solution makes the engine shaft more complex due to the presence of a third crankpin which increases the step between cylinders and the length of the crankshaft. The crankshaft becomes longitudinal and torsional flexible with negative repercussions over engine running

Our solutions

a) connecting-rod position

The connecting-rod (C) of inner piston (A) and the connecting-rod (D) of the outer piston (B), have the operating plane (c) and the operating plane (d) angle positioned against of a classical connecting-rod operating plane.

The engine uses on one side an inner piston (A) and on the other side an outer piston with two active ends (B) which glides on same axis with inner piston (A).

Piston with two active ends (B) has one end has the role of external piston (a) and the other one has the role of oval piston for the displacement compressor (b).

b) All joints made of walls with spherical form Joints made of walls with spherical form (i) (j) (l) (m) receive the efforts on a main body. The main body is a wall with spherical form. The concave part of the body take the compression efforts and the convex part take the decompression efforts.

b.1) Joint between piston and connecting rod

  • the joint made of walls with spherical form with pocket(i) take the compression efforts from a disk board (p) with concave center. The disk board (p) is radial fixed to inner piston (A) with a safety ring of trapezoidal section (8). Decompression efforts is retrieved through pocket (r) fixed on disk board (p).
  • joint made of walls with spherical form with pocket(l) is similar with joint(i). Joint made of walls with spherical form with pocket(l)differs from joint(i) by: it has in addition another hole (1) in disk board(p) through which passes an inlet pipe for compressed air.

b.2) crankshaft and connecting-rod assembly

  • joint made of walls with spherical from with ring (j) take the compression efforts from a barrel part (u) with spherical exterior and cylindrical hole interior. The decompression efforts is received by a ring (v) fixed on barrel part(u).
  • the mother inner connecting-rod(G) is fixed beside barrel part(u) through the finger (15).
  • The connecting-rod (C) puts the effort in crankpin (2), the connecting-rod (D) puts the effort in crankpin (3), both in phase opposition and which are part of a group of crankpins (f).
  • The group is fixed between two adjacent journal bearings (g) and they form the crankshaft (E).
  • Both connecting-rods(C) (D) have at the end joints made of walls with spherical form.
  • The connecting-rod (C) has a hollow body type (h) and at one end it has a joint made of walls with spherical form with pocket (j)
  • The connecting-rod (D) body is closed frame and composed of cross bar (4) and cross bar (5), linked with bars (6).
  • The joint made of walls with spherical form with two rings (m) is attached to cross bar (5) to the exterior of body

c) Overcharging circuit

The overcharging circuit (F) is composed from a compressor which has oval piston for the displacement compressor (b) , where an escape valve is mounted (17) . It continues with a central pipe (18).

Compressed air arrived in piston cooling chamber (11), passes through slide valve (w) which is formed between piston (a) and cylinder block (x), and then gets into combustion chamber.

Advantages of our solution:

  • None of mobile parts of the engine doesn’t need bolts assembly which results in better mounting time and lower costs.
  • Inclined functioning of connecting-rods allows simplification of the drive shaft. A crankpin is removed.
  • Connecting-rods positioning and the use of oval piston compressor results in lower the step between cylinders. So the engine will be shorter as length.
  • Using the piston with both active heads allows a better and simple handling of outer piston. As a result it’s obtained a mechanical compressor without own crankshaft, which is correlated in phase with the optimal transfer timing of compressed air in combustion chamber.
  • The overcharging circuit performs the following functions: forced cooling of the external piston and the heat from the cooling of external piston it is used to preheat the air going into combustion chamber.
  • The exhaust gases energy can be used to activate a turbine/electric generator producing electricity for external use.
  • All technical solutions simplify the construction of the engine and the assembly operation. Also the engine should perform better and it should have a better maintenance cycle.


The OPOC-DBV concept opens the way to a new generation of OPOC engines. The concept is completely different from conventional systems, proposing a courageous arrangement of the connecting rods, tilted sideways. First of all, any errors related to execution as well as those occurring during operation no longer affect the operation of the engines. Its construction is extremely simple because it can be assembled without screws.

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