The Compact Non Vibrating Endothermic Engine (CoNVEE in the following) is an internal combustion engine with reciprocating motion of the pistons, whose innovative architecture makes it more compact, given the same delivered power, with respect to the current state of the art. This happens both because the CoNVEE core occupies a very reduced volume, and also because it does not require the presence of any additional compensation or damping of mechanical vibrations. In fact all the moving parts of the CoNVEE are already internally compensated: they act in perfect anti-symmetry compensating each inertia force developed, excluding, of course, that of the motor shaft which is indispensable for the generation of the useful mechanical energy. The intrinsic compactness of the CoNVEE is made possible by the new and characteristic mechanism adopted for the motion transfer from the pistons to the motor shaft. The CoNVEE may be conveniently used with any type of propulsion fuel and, particularly, for those applications which require high power density and low vibration in the motor.