GB1571554A - Internal combustion engine precombustion chambers - Google Patents

Description

(54) INTERNAL COMBUSTION ENGINE PRECOMBUSTION CHAMBERS (71) I, DAVID MICHAEL DODD, a British subject, of 531, Tower Building, Water Street, Liverpool, Merseyside, do hereby declare the invention, which was communicated from EDGARDO HAROL DO HARDOY and EDUARDO JULIAN MANUEL ORDOQUI E ICETA, both Argentinian Nationals both of Sarmiento 643, Buenos Aires, Republica Argentina, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The subject of the present invention is improvements in internal combustion engines.

It is based essentially on making certain alterations to existing engines, especially in the cylinder head in those engines which have precombustion chambers which are, in part, hollowed out from the actual head and in part are in inserts which are screwed to the said cylinder head.

Thus, embodiments of the invention comprise an internal combustion engine having at least one piston arranged for reciprocation in a cylinder which communicates with a precombustion chamber bounded partly in a cylinder head of the engine and partly in an attachment to the cylinder head, said attachment having two bores therein leading into the precombustion chamber and respectively adapted to receive a fuel injector and a sparking plug, the axes of said bores intersecting at a point within that part of the precombustion chamber which is in said attachment.

The attached Figures illustrated the said improvements as follows: Figure 1 is a partial vertical cross section of an engine block, with the section passing through the axis of one of the cylinders, showing a cylinder head modified in accordance with this invention; and Figure 2 shows a cross section, on a plane with the outline II-II shown on Figure 1, of the insert which contains a part of the precombustion chamber, the other part of which is in the cylinder head.

As may be seen from Figure 1, the upper part 10 of a conventional engine block which, since it is known, is marked in broken lines, has cylinders in which pistons 11 travel. On the block 10 a cylinder head 1 is fixed in a known manner so that when the piston 11 arrives at its upper dead point it almost touches the head 1 as can be seen in Figure 1. In the head 1 there is hollowed out the part 2' of a precombustion chamber which, in the case illustrated is spherical and is supplemented by a hollowing out 2" which is made in an attachment 6 which is screwed to the head 1 by means of screws 5' which pass through holes 5 made in the said attachment 6, Figure 2. The attachment 6 may be one for each cylinder containing a piston 11, or one single one for all the cylinders. In the case illustrated, it is one for each cylinder.

The precombustion chamber 2' - 2" is connected directly to the cylinder in which the piston 11 travels by means of a passage which slopes due to the lateral position of the precombustion chamber 2' - 2" in relation to the cylinder with the piston 11.

The threaded holes 3' and 4' into which the injector 3 and the sparking plug 4, which can be of any of the known types, are screwed, are made in the attachment 6, out of centre in relation to the chamber 2' - 2".

The threaded holes 3' and 4' intersect at a point within that part of the precombustion chamber which is in the attachment 6. The working of the engine is that corresponding to a four stroke engine with the difference that it does not have a carburettor and that it only compresses air up to a certain moment at which, by means of the injector 3, it injects a quantity of liquid fuel; thereupon a spark is immediately produced which jumps between the electrodes 4" of the plug 4. The mixture of air and fuel is ignited in this way in the precombustion chamber 2' - 2", since there is practically no chamber in the cylinder,when the piston 11 reaches the upper dead point, and almost touches the head 1 as is illustrated in Figure 1. Then the ignited explosive mixture passes through the sloping passage 7 and drives the piston ll in the usual manner.In Figure 2, the visible part of the precombustion chamber 2" is reduced in diameter since the section ll-ll is taken almost through the top of the cap which is hollowed out in the attachment 6. The threaded hole 3' is shown for the most part by dotted lines since the sparking plug 4 forms with the injector 3 an acute angle in order to cause an eddy which facilitates the mixutre of the liquid fuel mist which discharges from the injector 3 with the compressed air in the precombustion chamber 2' - 2". The present invention converts engines of the Otto cycle to engines which are neither of the semi-Diesel cycle nor even less of the Diesel cycle by their low compression ratio, which undoubtedly allows them to burn various fuels such as, for example, Gasoil, Kerosene and other distillates, with the greatest mcchanical efficiency.This engine should not be confused with the one called the semi-Diesel engine since it does not need either a hot chamber or heating of the cylinder head in order to be started up. Instead, the method of heating the air or the fuel before they enter the cylinder is not used.

In detail and emphasising the advantages obtained; since, in the world motor market, it is not possible to rely on engines which can satisfy the present day requirements for the modern motor car as far as economy is concerned; the majority of the car manufacturers fit their vehicles with petrol engines with a heavy fuel consumption while others alter their vehicles by installing engines of other makes from the Diesel range in order to obtain greater fuel saving and the use of a cheaper type of fuel e.g. gasoil.While greater fuel saving is obtained, since the Diesel engine has a low consumption, there is the great disadvantage that it is hardly a suitable engine for the present day motor vehicle; its large size and weight make it unsuitable for light, fast vehicles while its slow, noisy running is a drawback to which there is virtually no solution, since it was not designed for such uses but rather for rough, heavy work such as goods lorries, agricultural and industrial machinery etc. where it is used with very satisfactory and effective results since speed and smooth running are not pre-requisites for such types of work.

The purpose of systems hereof is to provide the vehicle with a fast light weight engine, which is economic in use and smooth running. Special care is taken to retain all the original manufacturing features of the said engines to make them lasting and safe with the most effective possible alterations and to adapt them to fuels which are more readily available than petroleum such as gasoil, kerosene and other distillates.

In petrol driven engines, the original cylinder head 1 is replaced with a head designed hy ourselves, flattened in shape, and replacing the original combustion chamber with a precombustion chamber 2' - 2" designed by ourselves, (the design not being restrictive in its form) which, in general, is situated as per the appropriate design, on one side of the cylinder head 1. This precombustion chamber is machined to a spherical shape and divided into two parts, one 2' machined in the cylinder head, with its appropriate cooling and the other part 2" superimposed and with very little cooling; for enhancing the heating thereof, this precombustion chamber is fitted at the upper part with an injector 3 of the type used by Diesel engines and a permanent sparking plug 4 of the type used by the Delco Standar ignition engines. ("Delco" is a registered Trade Mark).In this precombustion chamber which has dimcnsions similar to those of the original chamber which it replaced, the same or a similar compression ratio is retained and a good eddy of air is produced in order to ensure that, during the compression stroke, the air and the fuel which is injected mix well; the fuel which is injected at high pressure comes into contact with the heated walls of the precombustion chamber for gasification therof, thereby allowing the mixture to ignite.

There is a great problem for the builders of Diesel engines in the design of the chambers where there is very little time available for the injection and the mixing with the air. Herein, there is no requirement for the high pressure of the Diesel engines for the ignition of the mixture; this allows the injection to be brought forward considerably in relation to the dead centre of the piston at the end of its compression stroke, thereby obtaining a better mixture of air and fuel; with ignition at the most effective point by an electric plug fed by a high power source.

Advantages of the system arise, since, by having low compression, between 6.5 and 10 to 1 compression ration, very smooth running results while all the useful cylinder capacity of the engine and its number of revolutions are taken advantage of without any risk of high pressure inside the engine.

The start, which is another critical point in the majority of Diesel engines, can be resolved in our system for such engines by using petroleum for starting up. Equipment hereof may then have a small auxiliary tank system (not illustrated) in or from which petroleum and gasoil can, and normally will, be mixed in equal quantities, connected to the injector pump, with an automatic cock to cut off the gasoil in favour only of the petroleum as a supply to or from the auxiliary tank, thereby ensuring a start which is no more difficult than that with an ordinary petroleum engine. When the engine is at a normal temperature, the cock will connect in the gasoil.

The use of the injector pump has been assisted by fitting to the front of the engine a new distribution box with the addition of two further gears, one being intermediary and the other at the end of the injection pump axle for the working thereof; the pump is a usual mass-produced one identical or similar to those with which Diesel engines are generally fitted; we will not, therefore, describe it in detail. The injectors 3 used are of the Bosch (Registered Trade Mark) type with nozzles of the same make, of the dowel type, thereby ensuring good gasification of the fuel used; neither this type of injector nor the nozzles are restrictive since identical results may be obtained with other similar ones. The precombustion chamber as described above is not restrictive in its form nor in the materials of which it may be manufactured.In the place of the original carburettor, a neck with a Venturi tube is installed connected to the injector pump regulator which, in all cases, is pneumatic.

Fuel filter: this is of the sealed unit and water trap type. The pump which supplies the fuel to the filters and the injector pump is the original one on the engine. The injection tubes are of the usual type for Diesel engines. It is also pointed out that, since there is no change of the compression ratio in the engine the same battery can be used for the vehicle and the same starting device. This system has shown, in the tests carried out using gasoil type fuels in petroleum engines, performances similar to the previous conditions with a fuel saving of approximately 30%.

Under no circumstances are any replacements or changes made to the basic parts of the engine such as the crankshaft. the pistons. the connecting rods, the bearings etc. which retain their shape and dimensions.

Engine cycle: as may be appreciated from the above description. the cycle for this engine is not exactly that of the Diesel engine nor that of spark ignition engines but it enjoys the advantages inherent in both systems. This is one of the reasons why this system is the most practical for a fast light-weight vehicle.

Working: During the intake stroke, the air enters the cylinder as a result of the suction caused by the piston moving downwards. Compression beings immediately after the intake stroke ends; its final value is less than that in Diesel engines since it reaches only approximately 10 Kg/cm2. The fuel is injected almost at the end of the compression stroke by means of a Diesel pump of a type in current use. As a result of the shape of the precombustion chamber fitted into the cylinder head (and we would repeat that the shape of the precombustion chamber is not restrictive) the air is compressed and takes on the form of a controlled eddy; this said eddy carries finely divided fuel in the precombustion chamber producing a perfect mixture of fuel and air which is ignited by an electrical sparking plug.The resulting combustion produces work during the expansion stroke and the exhaust valve subsequently opens with the piston returning to the upper dead point.

Naturally, there can be many modifications of details in the type of manufacture described, such as altering the shape of the precombustion chamber, the position of the injector or of the sparking plug.

WHAT WE CLAIM IS: 1. An internal combustion engine having at least one piston arranged for reciprocation in a cylinder which communicates with a precombustion chamber bounded partly in a cylinder head of the engine and partly in an attachment to the cylinder head, said attachment having two bores therein leading into the precombustion chamber and respectively adapted to receive a fuel injector and a sparking plug, the axes of said bores intersecting at a point within that part of the precombustion chamber which is in said attachment.

2. An internal combustion engine substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. using petroleum for starting up. Equipment hereof may then have a small auxiliary tank system (not illustrated) in or from which petroleum and gasoil can, and normally will, be mixed in equal quantities, connected to the injector pump, with an automatic cock to cut off the gasoil in favour only of the petroleum as a supply to or from the auxiliary tank, thereby ensuring a start which is no more difficult than that with an ordinary petroleum engine. When the engine is at a normal temperature, the cock will connect in the gasoil. The use of the injector pump has been assisted by fitting to the front of the engine a new distribution box with the addition of two further gears, one being intermediary and the other at the end of the injection pump axle for the working thereof; the pump is a usual mass-produced one identical or similar to those with which Diesel engines are generally fitted; we will not, therefore, describe it in detail. The injectors 3 used are of the Bosch (Registered Trade Mark) type with nozzles of the same make, of the dowel type, thereby ensuring good gasification of the fuel used; neither this type of injector nor the nozzles are restrictive since identical results may be obtained with other similar ones. The precombustion chamber as described above is not restrictive in its form nor in the materials of which it may be manufactured.In the place of the original carburettor, a neck with a Venturi tube is installed connected to the injector pump regulator which, in all cases, is pneumatic. Fuel filter: this is of the sealed unit and water trap type. The pump which supplies the fuel to the filters and the injector pump is the original one on the engine. The injection tubes are of the usual type for Diesel engines. It is also pointed out that, since there is no change of the compression ratio in the engine the same battery can be used for the vehicle and the same starting device. This system has shown, in the tests carried out using gasoil type fuels in petroleum engines, performances similar to the previous conditions with a fuel saving of approximately 30%. Under no circumstances are any replacements or changes made to the basic parts of the engine such as the crankshaft. the pistons. the connecting rods, the bearings etc. which retain their shape and dimensions. Engine cycle: as may be appreciated from the above description. the cycle for this engine is not exactly that of the Diesel engine nor that of spark ignition engines but it enjoys the advantages inherent in both systems. This is one of the reasons why this system is the most practical for a fast light-weight vehicle. Working: During the intake stroke, the air enters the cylinder as a result of the suction caused by the piston moving downwards. Compression beings immediately after the intake stroke ends; its final value is less than that in Diesel engines since it reaches only approximately 10 Kg/cm2. The fuel is injected almost at the end of the compression stroke by means of a Diesel pump of a type in current use. As a result of the shape of the precombustion chamber fitted into the cylinder head (and we would repeat that the shape of the precombustion chamber is not restrictive) the air is compressed and takes on the form of a controlled eddy; this said eddy carries finely divided fuel in the precombustion chamber producing a perfect mixture of fuel and air which is ignited by an electrical sparking plug.The resulting combustion produces work during the expansion stroke and the exhaust valve subsequently opens with the piston returning to the upper dead point. Naturally, there can be many modifications of details in the type of manufacture described, such as altering the shape of the precombustion chamber, the position of the injector or of the sparking plug. WHAT WE CLAIM IS:

1. An internal combustion engine having at least one piston arranged for reciprocation in a cylinder which communicates with a precombustion chamber bounded partly in a cylinder head of the engine and partly in an attachment to the cylinder head, said attachment having two bores therein leading into the precombustion chamber and respectively adapted to receive a fuel injector and a sparking plug, the axes of said bores intersecting at a point within that part of the precombustion chamber which is in said attachment.

2. An internal combustion engine substantially as herein described with reference to the accompanying drawings.