The present invention concerns an endothermic engine, working with an Otto-cycle and with a diesel-cycle, cha¬ racterized in a double combustion.

It is already well known that in the endothermic engines the exhaust gases have a considerable percentage of un- burnt hydrocarbons, beyond carbon monoxide and nitrogen oxides.

Of all said mixtures, the unburnt hydrocarbons and the carbon monoxide may be recycled because if they are put in an oxygenated ambient they may have a second and com¬ plete combustion, with the double advantage of a consi¬ derable increase of the total efficiency of the engine and of the nearly total elimination of the polluting components of the exhaust gases.

It is the aim of the present invention to allow above mentioned double combustion in endothermic engines with fuel or Diesel oil.

The aim set forth is reached by means of the engine ac¬ cording to the present invention, comprising means for the recollection of the gases not completely burnt dur¬ ing the explosion in one cylinder, which are sent to a further cylinder which, at the same time, aspires only

air or a mixture with a minimum percentage of fuel.

Said second cylinder therefore is working only in con¬ ditions of overfeeding, because in this phase the first cylinder acts like a pushing pump.

Of course the present invention will provide, in the va¬ riant of the Diesel-cycle engines, an additional injec¬ tion of Diesel oil - not the same quantity of the one present in the first cylinder - having the same purpose that the immission of little fuel percentage mixture as described above for the Otto-cycle.

The present invention will be described more in detail hereinbelow, according to the enclosed drawings.

Figure 1 shows a scheme of the coupling of two cylin¬ ders, without any variation of the distribu¬ tion relative to the first cylinder, with a contemporary aspiration, in the second cylin¬ der, of air or thin mixture and burnt gases.

Figure 2 shows a scheme of the phases of an engine ac¬ cording to the present invention in which fol- lowing to the modification of the distribution of the cylinder for the first combustion, and delaying the opening of the exhaust valve, the

aspiration in succession is obtained in.the second cylinder first of the air or eventual thin mixture, and then of the pressurized com¬ bustion gases.

Figure 3 shows a variant comprising two aspiration val¬ ves in the second cylinder, the first being connected with the aspiration box or with a small carburettor, and the second one with the exhaust of the first cylinder.

Relating now to the figures, in all variants the con¬ nection tube 3 between the first cylinder 1 and the se¬ cond cylinder 2 is present.

For what concerns the variant according to figure 1, the elbows of the engine shaft, relative to cylinders 1 and 2, are placed at 180°, and the first cylinder 1 aspires, through a tube 4, a mixture of air and fuel; the gases of the first co.bustion pass in the connec¬ tion tube 3 and get mixed with pure air or with a thin mixture caming from a tube 5 so as to reach the second cylinder 2 where the second combustion takes place with the final discharge of the gases through tube 6.

Relating to the variant of figure 2, a valve 7 is pre- ferrably provided in tube 7 of the carrying type.

The succession of the phases may be described as follows:

2 A = the exhaust valve of cylinder 1 opens at about -g of the running up of the piston so as to allow the cy¬ linder 2 to aspire - for about half the run - only pure air or thin mixture from tube 5; in connection tube 3 valve 7 is placed, of the door kind, moved by the pressure of the exhaust gases,and that will prevent the reflow of the exhaust gases into the a- spiration box.

B = All exhaust gases are flown into the second cylinder 2 and are now mixed with the aspired air or thin mixture.

C = The cylinder 2 is compressing the mixture of air and burnt gases, while cylinder 1 aspires a mixture or air to be mixed.

D = Cylinder 1 stops mixing burnt air and gases, while cylinder 1 aspires the mixture.

E = The cylinder 2 explodes while cylinder 1 finishes compressing the mixture.

F = Cylinder 1 explodes while cylinder 2 expells the ga¬ ses burnt twice.

In the variant according to figure 3, two aspiration val-

ves are provided in the second cylinder 2 because the a- spiration tube 3 is divided from the connection tube 3, and has the function of sucking the air or the thin mix¬ ture.

The functioning described hereinbefore is similar in the application of the present invention to Diesel-cycle motors with the sole difference that, when performing the second combustion, a diesel oil injection is prov- ided of a minor quantity than the one contained in cy¬ linder 1.