This invention relates to fuel atomising or pulverising devices for Diesel engines.
It is well known that incomplete pulverisation permits the accumulation on the piston of certain quantities of oil, with the result of decreasing the efficiency and giving rise, moreover, to actual danger owing to the presence in the cylinder of an ungoverned supply of oil.
The pulverising device described comprises three pulverising members grouped concentrically round a needle-valve of the type usually employed, and which is seated in the lowest of these members. This latter member, moreover, is fitted with a rearwardly projecting sleeve, which is adapted to enter a corresponding chamber or recess in the middle member, sufficient clearance being provided to form an annular chamber for admitting of the passage of the fuel.
A second and larger annular chamber is formed in the second member which is situated concentrically but externally to the first. This latter concentric annular chamber is connected to a small aperture which communicates with the supply of fuel, whilst the third and highest pulveriser member is in communication with the compressed air supply.
From the small inner annular chamber formed by the clearance between the first and second pulveriser members, the fuel passes from this chamber to the space surrounding the needle-valve, through small ducts formed in the top of the lower member, which ducts are directed tangentially towards the circumference of the needle-valve.
By means of this arrangement a spraying of the fuel at right angles to the current of air is effected. The fuel is thus carried forward in a spiral path, becoming more and more disintegrated as it progresses, and arriving finally at the injection nozzle in a very high state of pulverisation.