GB2060064A

GB2060064A - Internal Combustion Engine in which Incombustible Fluid is Supplied to at Least One Cylinder when Hot to Operate the Associated Piston

Info

Publication number: GB2060064A
Application number: GB8031195A
Authority: GB
Original assignee: Smee J A
Current assignee: Smee J A
Priority date: 1979-10-05
Filing date: 1980-09-26
Publication date: 1981-04-29
Also published as: GB2060064B

Abstract

In at least one cylinder 11 of the engine, a secondary injector 21 injects water in place of fuel injected via primary injector 18, when the temperature exceeds a predetermined value. This cylinder then runs after the manner of a steam engine until it has cooled to a second predetermined lower temperature when it is switched back to the fuel injector 18. In modifications, Figs. 3-6 (not shown) each combustion driven cylinder of the engine may have one or a plurality of steam-driven cylinders so associated therewith that its exhaust heats the steam-driven cylinder(s). The steam-driven piston(s) may be geared to perform two reciprocations for each reciprocation of the combustion driven piston. <IMAGE>

Description

SPECIFICATION Engine This invention concerns engines, more particularly internal combustion engines and has for its object to provide an engine construction which is considerably more economical to run than prior known constructions.

In general, conventional engines embody water cooling arrangements involving a water jacket surrounding the usual cylinder block of the engine and connected to an air-cooled radiator, cooling water circulating in turn through the block and the radiator. Such a cooling arrangement is, of course, wasteful, in that it releases energy to the air as unused heat. The problem to be solved by the invention is to provide means whereby use can be made of at least some of this heat in the driving of the engine, thereby reducing the fuel consumption of the engine.

To solve this problem, the present invention provides an internal combustion engine comprising cylinders each accommodating a respective reciprocating piston, primary fuel supply means for supplying combustible fuel to at least some of said cylinders, secondary vapourisable liquid supply means for supplying a vapourisable liquid, such as water, in liquid or vapour form, to at least some of said cylinders, and thermostatic control means operative upon the engine, or a part thereof, reaching a first predetermined temperature sufficient to ensure vapourisation of and rapid expansion of the liquid, when running on combustible fuel, to switch in the secondary liquid supply means to one or more of its cylinders to impart drive to the respective pistons by vapour expansion, and upon falling back to a second lower predetermined temperature, to switch off the secondary liquid supply means.

With such an arrangement, therefore, once the engine reaches an operating temperature which is sufficient to cause rapid expansion of the vapourisable liquid, the engine is switched over so that a selected number of its cylinders (which may be a single one of the cylinders, may be more than one such cylinder or may be all of the cylinders) have the vapourisable liquid supplied thereto, either as liquid or vapour, so that the selected cylinders then each operate by liquid expansion, utilising heat derived from the structure of the engine, somewhat after the manner of a steam engine, operating in the place of or as a supplement to the cylinders (or remaining cylinders) operating by fuel combustion.

The arrangement accordingly may be such that both the primary fuel supply means and the secondary liquid supply means are adapted to supply combustible fuel and vapourisable liquid respectively to all of the cylinders, the control means serving, at the first predetermined temperature, to switch off the primary fuel supply means to a number of the cylinders and to switch in the secondary supply means to the same cylinders or a smaller number of said cylinders.

Alternatively the arrangement may be such that the primary fuel supply means serves to supply combustible fuel to the cylinders of a first combustion-driven group of cylinders and the secondary liquid supply means serves to supply liquid or vapour to the cylinders of a second vapour-driven group.

In the latter arrangement, each cylinder of the vapour-driven group may be connected to a respective cylinder of the combustiondriven group for exhaust gases from the latter to pass through the cylinders of the vapour-driven group to transmit heat thereto. Then, a plurality of the cylinders of the vapour-driven group may be connected to each single cylinder of the cqmbustion-driven group.

The arrangement may be such that the pistons of the cylinders of the vapour-driven group associated with each combustion-driven cylinder are offset relative to one another in the operative cycle of the engine.

Moreover, the pistons of the vapour-driven group may be geared to operate at a greater reciprocating speed than the pistons of the combustion driven group, or at a lower reciprocating speed than the latter.

The engine of the invention may be a diesel engine, in which case the primary fuel supply means will comprise diesel injectors. The vapourisable liquid supply means may comprise water injectors. These latter injectors may be disposed to inject the readily-vapourisable liquid directly into the respective cylinders, for instance to impinge on a respective heat transfer plate or grill accommodated in said cylinders and in heat conducting communication with the cylinder block (or a cylinder head thereof) in which case it enters each cylinder as injected relatively-cold droplets; or it may be introduced by way of preheating passages (e.g. in the cylinder head or a heat-conducting structure secured thereto) so as to arrive at the respective cylinders at a temperature approaching that at which it will vaporise.It may also be introduced in prevapourised form.

The invention will be described further, by way of example, with reference to the accompanying drawings which illustrate various practical embodiments of the engine of the invention, it being understood that the following description is illustrative, and not restrictive, of the scope of the invention. In the drawings:-- Fig. 1 is a side elevation illustrating the basic details of a practical embodiment of the engine of the invention; Fig. 2 is an enlarged diagrammatic fragmentary sectional elevation illustrating one of the cylinders of the engine of Fig. 1; Fig. 3 is a view comparable with Fig. 2 but illustrating how, in the engine of the invention, one or more combustiondriven cylinders may each be associated with a respective vapour driven cylinder; Fig. 4 is a view similar to Fig.3 but showing another embodiment in which a combustion driven cylinder has a vapour-driven cylinder associated therewith; Fig. 5 is a diagrammatic sectional plan illustrating how, in the engine of the invention, one or more combustion-driven cylinders may each be associated with two vapour-driven cylinders; and Fig. 6 is a view comparable with Fig. 5 but wherein the or each combustion-driven cylinder is associated with four vapour-driven cylinders.

Referring firstly to Figs. 1 and 2, a practical embodiment of the engine of the invention comprises a cylinder block 10 embodying a plurality of cylinders 11 each accommodating a respective piston 12 connected by a respective connecting rod 13 to a crank shaft 14, fitted with a flywheel 15, from which power from the engine can be derived. The upper part of the block 10 is capped by a cylinder head illustrated diagrammatically at 16, having exhaust ports (not shown) registering with each cylinder 11 and opening to an exhaust manifold (not shown), exhaust valves (not shown) being provided to control the exhaust ports, these valves being driven, in known manner, in predetermined order from the crankshaft 14.Primary fuel supply means of the engine comprises a bank 17 of fuel injectors providing one fuel injector, illustrated only diagrammatically at 18 in Fig. 2, for each cylinder 11, the operation of these injectors 18 being synchronised with the exhaust valves and the reciprocating movement of the pistons 12 in exactly the same way as a conventional diesel engine.

The engine of the invention differs from the conventional engines in that neither the cylinder block 10 nor the cylinder head 16 is formed with conventional cooling water jackets. Both these components 10, 1 6 are substantially solid, being clad with relatively thick heat-insulating material, for instance asbestos wool or glass fibre thermal lagging, so as to minimise heat loss therefrom.

Fig. 2 merely shows the cladding 19 of the cylinder block 10, for convenience of illustration, but it will be appreciated that such cladding is, in practice, provided all around the engine.

The engine is further fitted with a secondary vapourisable liquid supply means in the form of a set 20 of injectors, providing one liquid injector 21 for each cylinder 1 these being disposed to draw water from a reservoir 22 and to inject it, as a fine spray (in the same way as the primary fuel supply injectors 18 inject fuel) into the respective cylinders 11 of the engine.

The nozzles of these secondary injectors 21 may be aligned with and each direct a respective water spray towards a respective heat-transfer grid, indicated diagrammatically at 23, mounted within each of the cylinders 11 so that the injected water will impinge against the respective grid 23. These grids 23 are in heat-conducting connection with the structure of the cylinder head 16 of the engine and accordingly the temperature thereof will be related to the temperature of the engine structure.

Additionally, a thermostatic control 24 is provided for controlling the fuel injectors 1 7/1 8 and the secondary injectors 20/21. This control 24 is disposed to sense the temperature of the cylinder head 16, for instance adjacent one end thereof and as near as possible to the upper part of one of the cylinders 11, so that the temperature sensed is near to that of the heattransfer grids 23.This control 24 is effective, upon sensing that a first predetermined temperature has been reached, to switch off the fuel injectors 1 8 of a number of the cylinders 11 (which may be one cylinder 11 only, or may be selected ones of the cylinders 11 , or may be all of the cylinders 1 1 ) so that fuel is not longer supplied thereto, and simultaneously to switch on the secondary injectors 21 of the same cylinders 11 to inject water therein. The control is further effective, upon the sensed temperature falling to a second predetermined temperature (which is lower than the first predetermined temperature) to switch the secondary injectors 21 off and to switch the fuel injectors 1 7/1 8 back on again, thereby to ensure that fuel is once again supplied to all of the cylinders 11.

The mode of the operation of the engine will readily be understood from the foregoing description. Upon initial start-up, the engine runs in exactly the same way as a conventional diesel engine. However, the heat insulating cladding 1 9 minimises the loss of heat from the engine so that its structure increases in temperature fairly rapidly until it reaches the first predetermined temperature which may, for instance, be of the order of 5000C.The thermostatic control 24 then switches the injectors 18 and 21 of the selected cylinders so that water is injected therein in the place of fuel, and these cylinders operate as a result of vapourisation and expansion of the water as has already been described, the necessary energy for this being derived from the heat contained in the engine structure and transmitted to the water and vapour at least partly by way of the heat transfer grids 23. So soon as the sensed temperature drops to the second predetermined temperature, of course, the engine returns to operating upon injected fuel in the normal way.

Naturally, an engine running in this way consumes less fuel than an equivalent watercooled or air cooled engine running continuously on injected fuel.

The number of cylinders which are switched over to water (or other readily-vapourisable liquid) injection can, of course, vary for example in accordance with the load being handled by the invention at any particular time, it being possible for instance, to arrange, in a four-cylinder engine, for one, two, three or four cylinders to be switched over to water, if desired with different cylinders, or different combinations of cylinders being switched over under different working conditions.

Fig. 3 illustrates how the engine of the invention may be constructed with combustiondriven cylinders and separate vapourised-liquid driven cylinders. In this embodiment, the cylinder block 10 comprises a plurality of combustiondriven cylinders 11 each provided with a respective fuel injector 18 and having a respective port 30 connecting it with a respective adjacent low-pressure steam-driven cylinder 31 accommodating a respective piston 32 which is of somewhat larger diameter than the combustion driven piston 12. The port 30 is controlled by a valve which is illustrated diagrammatically at 33 and which is shown as serving also as an injector for water droplets.

The steam driven piston 32 is geared to reciprocate at twice the speed of the combustiondriven piston 12, and the valve 33 is operative to inject water droplets into the cylinder 31 upon a thermostatic control (comparable with the control 24 of Fig. 1) sensing that the temperature of the engine exceeds a predetermined temperature, for example of the order of 5000 C. Accordingly, in normal running of the engine, it will run as a conventional diesel engine. However, when the temperature of the engine preceeds the predetermined temperature, the or each steam driven piston 32 becomes operative, providing four power strokes for each power stroke of the respective combustion-driven piston 12.

It will be observed in Fig. 3 that the combustion-driven piston 12 is disposed to be in advance of the steam driven piston 32, and this lag of the steam driven piston can ensure adequate expansion of the water droplets and mixture of the exhaust gases at the commencement of the working stroke of the steam driven piston 32.

The arrangement of Fig. 4 is similar to that of Fig. 3, but in this instance a duct 34 between the cylinders 11 and 31 is fitted with respective valves 35 and 36 for controlling respectively the passage of exhaust gases from the cylinder 11 to the cylinder 31 and the entry of such gases, together with water droplets or steam supplied by means of valve 37, into the duct 34.

Figs. 3 and 4 illustrate the case where one or more of the combustion-driven cylinders of the engine are provided with respective steam driven cylinders 31.

Fig. 5 shows diagrammatically an arrangement in which a single combustion-driven cylinder 11 is associated with two steam driven cylinders 31 and pistons 32, the arrangement being such that exhaust gases from the cylinder 11 can, when the engine reaches the predetermined temperatures, pass to the steam driven cylinders 32.

Fig. 6 illustrates a further alternative possibility in which each single combustion-driven cylinder 12 is associated with four steam driven cylinders 31, the mode of the operation of these embodiments of Figs. 5 and 6 being comparable with those already described in relation to Figs. 3 and 4 of the drawings.

Claims

1. An internal combustion engine comprising cylinders each accommodating a respective reciprocating piston, primary fuel supply means for supplying combustible fuel to at least some of said cylinders, secondary vapourisable liquid supply means for supplying a vapourisable liquid, such as water, in liquid or vapour form, to at least some of said cylinders, and thermostatic control means operative upon the engine, or a part thereof, reaching a first predetermined temperature sufficient to ensure vapourisation of and rapid expansion of the liquid, when running on combustible fuel, to switch in the secondary liquid supply means to one or more of its cylinders to impart drive to the respective pistons by vapour expansion, and upon falling back to a second lower predetermined temperature, to switch off the secondary liquid supply means.

2. An engine as claimed in claim 1 wherein both the primary fuel supply means and the secondary liquid supply means are adapted to supply combustible fuel and vapourisable liquid respectively to all of the cylinders, the control means serving, at the first predetermined temperature, to switch off the primary fuel supply means to a number of the cylinders and to switch in the secondary supply means to the same cylinders or a smaller number of said cylinders.

3. An engine as claimed in claim 1 wherein the primary fuel supply means serves to supply combustible fuel to the cylinders of a first combustion-driven group of the cylinders and the secondary liquid supply means serves to supply liquid or vapour to the cylinders of a second vapour-driven group of the cylinders.

4. An,engine as claimed in claim 3 wherein each cylinder of the vapour-driven group is connected to a respective cylinder of the combustion-driven group for exhaust gases from the latter to pass through the cylinders of the vapour-driven group to transmit heat thereto.

5. An engine as claimed in claim 4 wherein a plurality of the cylinders of the vapour-driven group is connected to each single cylinder of the combustion-driven group.

6. An engine as claimed in claim 5 wherein the pistons of the cylinders of the vapour-driven group associated with each combustion-driven cylinder are offset relative to one another in the operative cycle of the engine.

7. An engine as claimed in any of claims 3 to 6 wherein the pistons of the vapour-driven group are geared to operate at a greater reciprocating speed than the pistons of the combustion driven group.

8. An engine as claimed in any preceding claim where the primary fuel supply means comprises diesel injectors.

9. An engine as claimed in any preceding claim wherein the vapourisable liquid supply means comprises water injectors.

10. An engine as claimed in claim 9 wherein the water injectors serve to inject water directly into the respective cylinders to impinge on a respective heat transfer plate or grill accommodated in said cylinders.

11. An internal combustion engine substantially as hereinbefore described with reference to and as illustrated in Figs. 1 and 2, in Fig. 3, in Fig. 4, in Fig. 5 or in Fig. 6 of the accompanying drawings.