WO1981003524A1

WO1981003524A1 - Device for supplying steam into the inlet of an ic-engine

Info

Publication number: WO1981003524A1
Application number: PCT/SE1981/000162
Authority: WO
Original assignee: Andersson J
Priority date: 1980-06-05
Filing date: 1981-06-03
Publication date: 1981-12-10
Also published as: EP0053138A1; SE8004193L; SE428587B

Abstract

Device in an internal combustion engine for supplying water vapour to the intake gases of the engine, the water vapour being generated by heating of water or an aqueous mixture from a container (1) by means of the heat of the exhaust gases leaving the engine. The water vapour is generated in at least one steam generation member (7) of a heat conducting material arranged between the container (1) and the intake pipe of the engine, which steam generation member (7) is at least partially in contact with the exhaust gases and comprises a chamber (8) having at least one liquid inlet opening (6) and at least one outlet (9a, 9b) for the generated steam, and means (5) for maintaining a predetermined liquid level in the chamber (8), said steam generation member (7) preferably being arranged at or close to the exhaust port of the engine block.

Description

DEVICE FOR SUPPLYING STEAM INTO THE INLET OF AN IC-ENGINE

The present invention relates to a new device for supplying water vapour to the inlet gases of an internal combustion engine.

It is known that a reduced fuel consumption as well as a reduction of the carbon monoxide content of the exhaust gases may be achieved by feeding water vapour to the iniet gases of an internal combustion engine without any adverse effects on the engine peπormance. Simultaneously the engine has hereby been made to run quieter. Various devices have been proposed to effect such a water vapour addition, but the hitherto produced devices have - in so far as they have worked at all under practical operating conditions - been too expensive and complicated in relation to the attained fuel consumption or exhaust gas purification.

According to the invention there is therefore suggested a device for supplying water vapour to the inlet gases of an internal combustion engine, which, simultaneously with being simple and reliable, quite surprisingly has proved to be capable of giving a saving in fuel of about 25 to 35 % under normal operating conditions. The device according to the invention is characterized by the features given in the subsequent claims and which are explained more thoroughly below.

A basic concept of the invention is thus that water from a water container is heated in one or more steam generation members, which at least partially are in direct contact with the hot exhaust gases from the engine, preferably at or near the exhaust port of the engine block. The steam generation member comprises a heating body of heat conductive material, the outside of which at least partially is arranged in direct contact with the hot exhaust gases. In the heating body a cavity or chamber is arranged, which is designed to be partly, i.e. to a certain level, filled with water from the water container. The cavity or chamber is provided with at least one outlet for the generated steam in the space above the water surface. The steam outlet or outlets are connected to the intake duct or pipe for air and/or fuel-air mixture. The above mentioned steam generation member may be designed in many different ways within the scope of the invention. Thus, it may e.g. consist of a substantially horizontal, straight or possibly curved pipe arranged in the exhaust manifold of the engine, the pipe cavity then serving as the steam generation chamber. Further, e.g. one or more manifold pipes may be provided with a double-walled section, the interspace between the walls then serving as the steam generation chamber. According to a preferred embodiment of the invention, however, the steam generation member preferably consists of a body, preferably an elongate washer or plate, designed to be inserted between the exhaust manifold and the engine block. Within said washer or plate one or more steam generation chambers are arranged and it is provided with passages corresponding to the exhaust ports (and possibly - depending on the type of eingine - intake port) of the engine block. Such a spacer washer is easy to mount and does not disturb the flow pattern of the exhaust gases.

Through the fact that, as described above, the steam generation chamber is arranged in such a way that the generated steam mainly is drawn off directly from the space above the liquid surface, the entrainment of water drops is reduced. Preferably, however, a water trap is arranged between the steam outl et or outlets and the engine- Water from the container is continuously fed to the steam generation chamber, either through gravity or via a pump device, and a suitable liquid level is continuously maintained in the cavity or chamber of the steam generation member by the aid of suitable means, e.g. a float valve, one or more moisture sensors in combination with a solenoid valve, or the like, arranged before the steam generation chamber.

The dimensions of the steam generation chamber or chambers and th e liquid level thereof is adapted so that an appropriate quantity of water is fed to the steam generation chamber. A suitable amount of water has proved to b e about 1 to 5 dl of water/liters of fuel, but also a greater or smaller amount of water may be used.

In case of, for example, a carburettor engine the generated steam may be supplied before or after the carburettor. In the latter case a suitable valve device is arranged, which adjusts the steam quantity in dependence of the throttle position. The device according to the invention may, of course, also b e used in engines without a carburettor - both petrol and diesel engines.

The invention is described in more detail below with regard to some specific embodiments thereof with reference to the accompanying drawings, wherein

Fig. 1 schematically shows a water vapour supply system of the invention,

Fig. 2 is a schematic view of an embodiment of a steam generation member of the device according to the invention, Fig. 3 and Fig. 4 are variations of another embodiment of the steam generation member,

Fig. 5 is a section along A-A in Figs. 3 and 4, and

Fig. 6 is a corresponding section as in Fig. 5 of a variation of the embodiment of Figs. 3 and 4. In the water vapour supply system of the invention shown in Fig. 1 , a water container or tank 1 is connected to a pump device 3 through a conduit 2.

The latter is via a conduit 4 connected to a level control 5, e.g. a float valve, which in turn through a conduit 6 is connected to a heating member or a steam generation element 7 of heat conducting material. The conduit 6 opens into a passage or cavity 8 in the steam generation member 7. The two ends of the passage or cavity 8 are each connected to steam conduits 9a, 9b, opening into a water trap 10. The top portion of the water trap 10 is connected to the intake pipe (not shown) of an internal combustion engine through a conduit 1 1. Depending on how this connection is arranged, a valve means 12 is possibly disposed between the water trap 10 and the intake pipe. From the bottom of the water trap 10 a return conduit 13 leads back to the conduit 6 between the level control 5 and the steam generation member 7. The steam generation member 7 is arranged such that it at least partially is in direct contact with the hot exhaust gases from the engine. This can be realized in various ways, e.g. by placing the steam generation member 7 completely or partially within the exhaust manifold of the engine as in Fig. 2, or by providing it in the form of an insert plate between the exhaust manifold and the engine block, as is further explained below in connection with Figs. 3 and 4. In operation water is pumped from the container 1 to the steam generation member 7 by means of the pump 3. A suitable water level 14 is continuously maintained in the cavity 8 by means of the level control 5, which also is arranged to control the pump 3. The level control 5 may, as mentioned above, suitably be a float valve, but the desired water level may, of course, also be adjusted by other means, e.g. as described in connection with Fig. 3 below. The hot exhaust gases emit heat to the heat conducting material of the steam generation member 7, thereby heating the water in the cavity. The cavity 8 will thus function as a steam generation chamber, and through the reduced pressure in the intake pipe of the engine the generated steam is sucked through the conduits 9a, 9b to the water trap 10 and further to the intake pipe through the conduit 1 1. Water drops which have been entrained to the water trap are separated therein and return to the conduit 6 through the draining conduit 13. Since a steam outlet is arranged at each end of the steam generation chamber 8, one of the two steam outlets will, independently of the inclination of the vehicle, always have a free passage for the steam. In such a way the entrainment of water drops is reduced substantially.

In Fig. 2 the steam generation member is a pipe 15, e.g. of copper, which is substantially horizontally arranged in an exhaust manifold 16. In the shown case the pipe 15 is intended to be disposed approximately along the engine block, the exhaust gases entering the manifold at the top of the Figure. On both sides of the exhaust manifold 16 two steam conduits 17, 18 are connected, which lead to the water trap shown in Fig. 1. The water is supplied at one end 15a of the pipe 15, and the desired liquid level 19 in the pipe is adjusted with the level control 5 in Fig. 1, e.g. to half the "height". The hot exhcust gases in the manifold 16 flush around the pipe 15, water being transformed into steam and led up through the steam pipes 17, 18 and then sucked into the engine as described above.

In Fig. 3 there is schematically shown another embodiment of the steam generation member, viz. in the form of an elongate washer or plate designed to be inserted between the exhaust manifold and the engine block. In the plate ports 20 are provided, which have substantially the same dimension as the corresponding ports of the engine block and exhaust manifold, respectively. Within the plate a cavity 21 is provided, to which a water inlet conduit 22 and two steam conduits 23 are connected. The cavity 21, which suitably extends along the whole plate, may have an arbitrary cross-section, e.g. circular as in Fig. 3 and Fig. 5. The cavity or steam generation chamber 21 may be a cavity within the plate material or may consist of a pipe or analogous, which may be made of the same or of another material than the plate material, inserted in to such a cavity. The plate may e.g., consist of an aluminum block, in the lower part of which a copper pipe has been fitted into a bore therein or been embedded when casting the block. The plate or heat body is further provided with holes 24 for the mounting bolts of the exhaust manifold.

In the same way as in Fig. 2 the cavity or pipe 21 is maintained filled with water to a suitable level by means of the level control 5 (Fig. 1). The hot exhaust gases discharged through the ports 20 of the plate heat the latter, and the heat is conducted through the material to the cavity 21 and heats the water to generate steam. The generated steam leaves through one or both steam pipes 23 (depending on the inclination of the vehicle). The steam pipes 23 are, in the same way as above, suitably connected to a water trap, from where the separated steam is sucked into the engine. Compared with, as in Fig. 2, placing a pipe 15 within the exhaust manifold, no disturbance of the exhaust gas flow in the manifold is obtained when using an insert plate according to Fig. 3.

An alternative level control device is schematically indicated in Fig. 3. Two moisture sensors 26 are each carried by T-connections 27 at the top side of the horizontal sections of the two steam conduits 23, so that they project down into the continuation of the cavity 21 formed by the steam pipes. The sensors are preferably mounted to be vertically adjustable, e.g. by means of a screw device (indicated by 29 in Fig. 3). The moisture sensors 26 may be of any conventional type, such as those used for level controls, for leakage detection or the like. Through a suitable circuit not shown t ey are arrange to actuate a so lenoid valve 28 at the water inlet 22 adjacent to the plate member. The sensitivity of the moisture sensors 26 is adjusted so that they only sense the water phase (and thus not the vapour), and they are adjusted vertically to detect a desired level in the cavity 21. The moisture sensors may, for example, be connected to the solenoid valve 28, so that the valve opens when none of the sensors detects water (AND-function) and closes when either of the two sensors indicates water contact (OR-function).

The cross-section form of the insert plate may e.g. be rectangular as in Fig. 5, but may, of course, also be designed in any suitable way, e.g. as in Fig. 6 to accomodate a larger cavity 21a which in the shown case has a rectangular cross-section.

Fig. 4 shows a variation of the insert plate of Fig. 3 designed for engines having the intake and exhaust ports on the same side of the engine block. In the shown case an intake port 25 is provided in the middle of the insert plate, exhaust ports 20 being provided on both sides thereof.

As previously mentioned the steam from the water trap 10 may, for example, in case of a carburettor engine, be fed to the engine before, in or after the carburettor through the steam pipe 1 1. If it is supplied at a point downstream the carburettor throttle, a suitable valve means 12 (Fig. 1) is, however, suitably arranged between the water trap 10 and the steam intake, point, which valve in any suitable way is arranged to be controlled by the opening of the carburettor throttle. The valve means 12 may e.g. be arranged to be controlled by "the vacuum" of the intake conduit. The water trap 10 of Fig. 1 may be any suitable conventional water trap, such as those used in compressors and the like. A simple and well operating water trap for the purposes of the invention may consist of a horizontal cylinder-shaped can having approximately the cross-section shown in Fig. 1 and having correspondingly arranged steam inlets at the sides and steam and water outlets at the top and bottom thereof, respectively.

The water container 1 (a suitable volym is e.g. about 30 to 40 liters) may be disposed at any suitable place in the vehicle. Preferably, however, it is placed in the engine house. In case it is located in another place a suitable anti-freezing agent, e.g. ethanol, must be added to the water to prevent freezing in the winter time. If it is placed in the engine house this will not be necessary, since possibly frozen water in the tank 1 is quickly thowed by the engine heat after the engine has been started. Heating coils are suitably provided within the tank 1 to preheat the water, e.g. to about 60°C, and thus give a quicker and more effective steam generation member. In a vehicle having a liquid cooling system suitable cooling coils may thus e drawn through the tank 1.

The steam supply system according to the invention is simple to mount, particularly the embodiment of an insert place according to Figs. 3 and 4. It is further very reliable and requires a minimum of maintenance. As mentioned previously a fuel saving of about 25 to 35 % is obtained at normal operating conditions, while simultaneously the carbon monoxide content of the exhaust gases is reduced considerably and the engine is caused to run quieter. The reduced fuel consumption obtained is illustrated by the results from a laboratory test, which was performed with a Volvo B16 petrol engine converted to a marine design and with a Schenk brake test-bed, and shown in the Table below. A syst em according to Fig. 1 was used, the steam generation member 7 being comprised of a straight copper tube having a diameter of 15 mm and being arranged in the exhaust manifold as in Fig. 2. The generated steam was fed to the air cleaner.

As appears from the Table above, an increase of the efficiency of about 23% was obtained for a water vapour supply corresponding to about 25 % by weight of the supplied fuel quantity. The test was performed at full speed performance, and an even greater increase of the efficiency would therefore be expected for normal driving. This is confirmed by a test made with a device according to the invention (Fig. 2) mounted in a passenger car. During about 60,000 kilometers' driving a lowered fuel consumption from 0,097 1/km to 0,065 1/km was obtained. Further, a reduction of the CO content of the exhaust gases of about 8 times was observed.

The invention is, of course, not restricted to the above particularly described and shown embodiments, but many modifications and variations are possible within the scope of the subsequent claims. The engine or corresponding engine parts may, of course, already at the manufacture thereof be provided with or adapted to the device of the invention.

Claims

1. A device in an internal combustion engine for supplying water steam to the intake gases of the engine, the water vapour being generated through heating of water or an aqueous mixture from a container (1) by means of the heat of the exhaust gases leaving the engine, characterized in that it comprises a steam generation member (7) of a heat conducting material arranged in close connection to the exhaust port of the engine block and at least partially in direct contact with the exhaust gases and comprising a steam generation chamber (8) having at least one liquid inlet opening '(6) and at least one outlet (9a, 9b) for the generated steam, means (5) to maintain a predetermined liquid level in the chamber (8), and a water trap (10) arranged between the steam outlet (9a, 9b) and the intake pipe of the engine for separation of water drops entrained by the steam.

2. A device according to claim 1, characterized in that the steam generation member (7) substantially is comprised of a tube or tube system (15) arranged substantially horizontally in the exhaust manifold (16).

3. A device according to claim 1, characterized in that the steam generation member (7) consists of an element designed to be inserted between the engine block and the exhaust manifold, which element is provided with, on one hand, one or more exhaust through ports (20), which connect the exhaust port of the engine block with the exhaust manifold, and, on the other, a cavity (21) arranged as said steam generation chamber.

4. A device according to claim 3, characterized in that the steam generation member is an elongate insert plate, wherein said cavity consists of an essentially horizontal, longitudinal passage (21) provided in the plate, said passage having a liquid inlet (22) and steam outlets (23) arranged at the end parts thereof.

5. A device according to any one of the claims 1 to 4 in carburettor engines, characterized in that the water vapour is supplied after the carburettor, and that it comprises means (12) for controlling the water vapour supply in dependence of the fuel quantity leaving the carburettor.

6. A device according to any one of claims 1 to 5, characterized in that the container (1) is provided with heating means (30).

7. A device according to claim 6, characterized in that the heating means (30) comprise a tube system connected to the cooling water system of the engine.

8. A device according to any one of claims 1 to 7, characterized in that the water trap (10) is a horizontal, substantially cylinder-shaped container having steam inlets at the end faces, one or more steam outlets arranged at the top and at least one liquid outlet arranged at the bottom thereof.

9. A device according to any one of claims 1 to 8, characterized in that said means (5) for maintaining the predetermined liquid level in the chamber (7 ) comprises liquid level sensing means (26) arranged to actuate control valve means (28) at the liquid inlet opening (6) of the steam generation chamber (8).

10. A device according to claim 9, characterized in that said liquid level sensing means (26) comprise at least one moisture sensor.