US2947295A - Internal combustion engines - Google Patents

Description

Aug. 2, 1960 Filed June 18. 1957 F. M. ASPIN INTERNAL COMBUSTION ENGINES 5 Sheets-Sheet 1 FM AsP INVENTOR BY HC.

ATTORNEY Aug. 2, 1960 F. M. ASPIN INTERNAL COMBUSTION ENGINES 5 Sheets-Sheet 2 Filed June 18, 1957' F M. Asf

INVENTOR ATTORNEY Aug. 2, 1960 Filed June 18, 195'! F. M. ASPIN INTERNAL COMBUSTION ENGINES 5 Sheets-Sheet 3 F M. P"-

INVEHTOR BY HCB IMM M ATTORNEY Aug. 2, 1960 F. M. ASPIN 2,947,295

INTERNAL COMBUSTION ENGINES Filed June 18, 1957 5 Sheets-Sheet 4 E M. Asp

mvENTbR BY H Bw ATTORNEY Aug. 2, 1960 F. M. ASPIN INTERNAL COMBUSTION ENGINES 5 Sheets-Sheet 5 Filed June 18, 1957 INVENTOR BY HC- B M ATTORNEY INTERNAL COMBUSTION ENGINES Frank Metcalf Aspin, Alderley Edge, England, assignor of one-half to F. M. Aspin Engines Limited, Manchester, England Filed June 18, 1957, Ser. No. 666,378

Claims priority, application Great Britain June 23, 1956 6 Claims. (Cl. 123-75) This invention relates to internal combustion engines of the kind in which the combustible fuel is supplied as a mixture of air and fuel metered by a carburettor or other device, as opposed to mechanical injection of neat fuel. The invention is particularly, though not exclusivey, applicable to internal combustion enginesof the kind described in -U.S. Patent No. 2,283,594 having a rotary valve in which is formed a chamber the volume of whichis a major portion of the combustion space at the moment of maximum compression.

It is well known that the scavenging of the residual products of combustion is a desirable factor in the design of an internal combustion engine. To obtain maximum performance it is essential to provide for as complete scavenging as possible and in achieving this by adopting Wide over-laps in valve timing there is a consequent loss of fuel to the exhaust gases under the varying conditions which obtain.

One known way of overcoming these losses is by the use of mechanical injection into the cylinder direct or in the inlet port, but such mechanical injection involves considerable expense and complication and has other inherent disadvantages.

The object of the present invention is to effect improved scavenging and provide greater general efficiency in an internal combustion engine, with particular, but not exclusive, application to a rotary valve engine as aforesaid and with general application to more conventional engines having poppet or sleeve valves.

According to the invention an internal combustion engine of the kind referred. to is characterised by means for supplying separately to the cylinder, respectively a combustion-supporting gas, such as fuelless air and a rich gaseous mixture of fuel such as a liquid fuel suspended is air, in such manner that the said combustion-supporting gas is used both for scavenging and .to combine with the rich mixture in the desired proportion for combustion, whereby loss of a proportion of the said combustion-supporting gas with the exhausting products of a preceding combustion in the cylinder can provide more complete scavenging substantially without loss of fuel.

The internal combustion engine aforesaid may be further characterised in that the means for admitting the rich gaseous mixture is so arranged as to delay admission until scavenging has been substantially completed; or further characterised in that the means for admitting the rich gaseous mixture is so arranged as to delay admission until loss of such mixture to the exhaust does not occur.

The invention will be described hereinafter by Way of example with reference to several arrangements in which the said combustion-supporting gas is fuelless or fuel free air and the rich gaseous mixture consists of an atomised or vapourised liquid fuel in air in proportions to form a combustible but so-cal1ed rich mixture but the invention is not limited thereto. For instance, the combustion-supporting gas could be a weak but combustible mixture which could be oxygen enriched, whilst the com- States atent i Patented Aug. 2, 1960 '4-cyc1'e internal combustion engine and fuel metering device made in accordance with the present invention;

Fig. 2 is a diagrammatic section at right angles to Fig. 1;

Fig. 3 is a diagrammatic plan of the rotary valve and metering device of the engine shown in Fig. 1;

Fig. 4 is a section on line A-A showing the rotary valve fully open to exhaust;

:Figs. 5, 6, 7, 8, 9 and 10 are sections showing further positions of the rotary valve;

Fig. 11 is a diagrammatic sectional plan of valve gear and fuel metering device for two adjacent cylinders of a multi-cylinder engine; and

Figs. 12, 13, 14, '15, 16 and 17 are sectional views similar to 'Figs. 5 to 10, but showing a modification of the invention.

As shown in Figs. 1 to 3 the engine comprises a cylinder .10, crankshaft 11, piston 12 and connecting rod 13. At the top of the cylinder is a rotary valve (rotor) 14 housed in a plug-like member (stator) 15, the piston being shown in the top dead centre position. -In the rotor 14 is the combustion chamber 16 representing the major portion of the combustion space at maximum compression, the chamber however being shown for the inlet cycle in communication with the induction pipe 17. A carburettor 18 is shown connected to the induction pipe having separate passages 19 and 20, for fuelless air and for a rich mixture of fuel and air respectively. The separation of these passages Within the carburettor by the partition 21 is continued in the induction pipe by a partition 17a and in the induction passage of the stator by the partition 15a. The carburettor shown includes diagrammatically a float chamber 21, fuel jet 22 and dual butterfly valve 23a, 2312. In the stator is also shown the exhaust passage 24. The means for driving the rotary valve are shown diagrammatically including a shaft 25.

In operation Fig. 4 shows exhaust fully open and Fig. 5 shows the rotor in its position prior to the commencement of the inlet cycle. Fig. 6 shows the rotor in topdead-centre position with relative overlap through the combustion chamber between the fuelless air passage 19 and the exhaust so that scavenging is in full process. Fig. 7 shows the end of scavenging with the chamber closed to the exhaust port and about to open to the passage 20 for the rich air/fuel mixture. Figs. 8, 9 and 10 show further progressive stages in the position of the rotor to the end of the inlet cycle, the fuelless air passage having been closed in Fig. 9.

As will be obvious, the initial admission of fuelless air enables scavenging to be effected so that contamination is substantially reduced whilst loss of fuel to the exhaust is substantially eliminated. This gives possibilities for an increase of power and reduced tendency to detonation. Also, whereas in a multicylinder engine the induct-ion manifold is heated to assist distribution, cold air can be used for the major portion of the ultimate charge and therefore a greater volumetric efliciency can be obtained. At the same time the rich fuel/air mixture can be heated to assist distribution without the same proportionate loss of volumetric .efi'iciency.

Fig. 11 is a diagram for the rotors 26, 27 of adjacent cylinders supplied by an induction manifold 28 from a single carburettor 29.

34 t on"- each side t-lflei-e't if. sequence of figures, ri-ot only-is fuelless -air provided'for scaven'gingj but also during thela'stpart of the induction cycle which nonnally 'passes 'bottom dead-centre and As shown in Figs, 12 to 17 inclusive the rotor 39 in the stator-31 is the same as the rotor 14, but the stator inlet passage is divided additionally to provide a central rich mixture passage 32 and fuelless air passages 33, :As can'be seen from the at which stage, under certain quite normal conditions, blow-back through the carburettor occurs with loss of fuel. The cutoff of the rich mixture results in the last part of the induction vo lume'b'ei ng'fuelless and thereforeany blo'w back will be'substantially fuelless.

Although'in the drawings, the division of the passages is shoWn as-if parallel totheaxis'of the rotor, andthe passages of equal cross section, the/above can be varied rotatable about the axis of said cylinder, a curved combustion chamber in said valvein communication with said "cylinder and having a lateral opening, an exhaust 'port in-said head adapted to communicate with said opening, at least one inlet port in said head adapted to communicate with said opening, said valve adapted to sweep said exhaust and inlet ports successively, a plurality of inlet passages for combustion supporting air and rich fuel-mixture respectivelyincommnnication with said inlet port, said air passage being in communication with said inletiport whilesaidexhaust port is open.

2. 'An internal combustion engine according to claim 1 further characterized in that the passage for admitting the' rich gaseous mixture is closed by said valve as to delay admission until scavenging has been substantially completed and the exhaust pen is fully closed.

3. An internal combustion engine according to claim 1 further characterized inthat the said complementary inlet port in the housing is divided into two ports, one for each'separate supply.

4. An internal combustionengine accordingtoclaim 1 further characterized in that the sub-'division is substantially medially arranged.

5. An internal combustion engine according to claim 1 further characterized in that the complementary inlet port in the housing is subdivided substantially axially into three areas to provide a medial area for the rich gaseous mixture 'and' sideareas for the combustion-supporting gas.

6. in combination With an internal combustion engine according to claim 1 a carburettor having separate passages for mixture and fuelless air with throttle mechanism in each coupled the one to the other for movement by a common control. 7

References Cited in the file of this patent UNITED STATES PATENTS 1,365,564 Strickland Jan. 11, 1921 1,896,163 Champion Feb. 7, 1933 1,927,368 Kjaer Sept. 19, 1933 2,230,740 Birkigt Feb. 4, 1941 2,240,088 Birkigt Apr. 29, 1941 2,242,990 Brown May 20, 1941 2,283,594 Aspin May 19, 1942 2,698,611 Knudsen Jan. 4, 1955

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