Atomizing Device

1. Field of the Invention

This invention relates to an atomising device.

2. Description of the Prior Art

A conventional multi-cylinder, petrol, internal combustion engine has a cylinder head with a row of inlet ports at one side. The inlet ports are connected to an inlet manifold leading from a carburettor to the inlet ports. The carburettor atomises the petrol fuel and thus produces a mixture of air and petrol particles which is conducted by the inlet manifold and the inlet ports to the engine cylinders for combustion.

This conventional arrangement has the disadvantage that the petrol particles tend to coalesce as they travel along the manifold and the ports and so enter the cylinders in a condition less suited to efficient combustion than the condition in which they left the carburettor.

According to the present invention, there is provided an atomizing device comprising a permeable member which is comprised of a porous substance.

This atomising device has the advantage that it can be arranged downstream of the carburettor in a conventional, petrol, internal-combustion engine in order to re-atomize the petrol particles in the mixture of air and petrol particles, so that the size of the petrol particles entering the cylinder is more suited to efficient combustion.

In order that the invention may be clearly understood and readily carried into effect reference will now be made, by way of example, to the accompanying drawing, which diagrammatically illustrates parts of an internal combustion apparatus.

Referring to the drawing, a petrol, internal combustion engine has a cylinder head 1 with a row of inlet ports at one side, one of the ports being seen and referenced 2. Associated with the inlet ports are respective inlet valves mounted in the cylinder head, one of the valves being seen and referenced 3. The inlet ports are connected to an inlet manifold 4 leading from a carburettor 5 to the inlet ports. As will be appreciated, this arrangement is conventional, the carburettor atomising the petrol, and the inlet manifold and ports conducting the mixture of air and petrol particles produced by the carburettor to the cylinders of the engine for combustion. However, this conventional arrangement has the disadvantage that the petrol particles tend to coalesce as they travel along the manifold and the ports, and so enter the cylinders in a condition less suited to efficient combustion than the condition in which they left the carburettor. To overcome this disadvantage of the conventional arrangement, the apparatus shown has interposed in the inlet duct system disintegrators disposed at the transitions between the manifold 4 and the inlet ports. There is one disintegrator for each inlet port, that for the port 2 being referenced 6. The disintegrators serve to re-atomise the petrol particles passing through them en route to the cylinders. The nearer the disintegrators to the cylinders, the more effective the disintegrators become, and they are therefore placed as near to the cylinders as is practicable.

Each disintegrator is disposed nearer to its cylinder than to the carburettor 5, and presents to the approaching mixture an exposed area which closes the inlet port but is covered with sharp-edged small holes which extend through the disintegrator. The proportion of hole area to total exposed area of the disintegrator is at least 80%. It needs to be relatively rigid in order to withstand the heavy fluctuating pressure pulses which occur in the inlet duct system. The disintegrator consists of a circular disc of a thickness of between 0.08 and 1.00 inch. It is comprised of a porous substance, the number of pores per linear inch being between 10 and 80, preferably between 15 and 45. The porous substance is a porous metal, preferably a foamed metal. The foamed metal can consist of nickel-chrome alloy or nickel. Such foamed metal can be made by plating a foamed plastics with the metal and then removing the plastics by heating in a vacuum furnace.

In a particular experimental example, I used as the disintegrators circular discs made by plating a reticulated polyurethane foam with nickel-chrome alloy and then removing the polyurethane by heating in a vacuum furnace. The foamed metal had between 15 and 25 pores per linear inch (I found about 20 pores per linear inch to be especially suitable). Each disc was arranged in the position shown in the drawings and I experimented with various disc thicknesses of between 0.08 and 0.50 inch, all of which proved relatively successful. The thickness of the disc of course determines to some extent the strength of the disc and thus its working life under the pulsating pressure and varying temperature conditions which obtained.

The permeable member could be in a form other than that of a circular disc, for example could be a cone, or a cylinder closed at one end.