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

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-walJed 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 t exhaust manifold and the engine block. Within said washer or plate one or mo steam generation chambers are arranged and it is provided with passag corresponding to the exhaust ports (and possibly - depending * on the type eingine - intake port) of the engine block. Such a spacer washer is easy to mou and does not disturb the flow pattern of the exhaust gases. Through the fact that, as described above, the steam generation chamb is arranged in such a way that the generated steam mainly is drawn off direct from the space above the liquid surface, the entrainment of water drops reduced. Preferably, however, a water trap is arranged between the steam outl or outlets and the engine- Water from the container is continuously fed to the steam generati chamber, either through gravity or via a pump device, and a suitable liquid lev is continuously maintained in the cavity or chamber of the steam generati member by the aid of suitable means, e.g. a float valve, one or more moistur sensors in combination with a solenoid valve, or the like, arranged before t steam generation chamber. The dimensions of the steam generation chamber or chambers and th liquid level thereof is adapted so that an appropriate quantity of water is fed t the steam generation chamber. A suitable amount of water has proved to b • about 1 to 5 dl of water/liters of fuel, but also a greater or smaller amount water may be used. In case of, for example, a carburettor engine the generated steam ma be supplied before or after the carburettor. In the latter case a suitable valv device is arranged, which adjusts the steam quantity in dependence of th throttle position. The device according to the invention may, of course, also b used in engines without a carburettor - both petrol and diesel engines. The invention is described in more detail below with regard to som specific embodiments thereof with reference to the accompanying drawing wherein Fig. 1 schematically shows a water- vapour supply system of th invention, Fig. 2 is a schematic view of an embodiment of a steam generatio member of the device according to the invention, Fig. 3 and Fig. are variations of another embodiment of the stea generation member, Fig. 5 is a section along A-A in Figs. 3 and , and Fig. 6 is a corresponding section as in Fig. 5 of a variation of th embodiment of Figs. 3 and . 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 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 mani old 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 1 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 si es the exhaust manifold 16 two steam conduits 17, 18 are connected, which lead the water trap shown in Fig. 1. The water is supplied at one end 15a of the p 15, and the desired liquid level 19 in the pipe is adjusted with the level contro in Fig. 1, e.g. to h .'f the "height". The hot exhcust gases in the manifold 16 fl around the pipe 15, water being transformed into steam and led up through steam pipes 17, IS and then sucked into the engine as described above. In Fig. 3 there is schematically shown another embodiment of the ste generation member, viz. in the form of an elongate washer or plate designed be inserted between the exhaust manifold and the engine block. In the pl ports 20 are provided, which have substantially the same dimension as t corresponding ports of the engine block and exhaust manifold, respective Within the plate a cavity 21 is provided, to which a water inlet conduit 22 a two steam conduits 23 are connected. The cavity 21, which suitably exte along the whole * plate, may have an arbitrary cross-section, e.g. circular as Fig. 3 and Fig. 5. The cavity or steam generation chamber 21 may be a cavi within the plate material or may consist of a pipe or analogous, which may made of the same or of another material than the plate material, inserted in such a cavity. The plate may e.g., consist of an aluminum block, in the lower p of which a copper pipe has been fitted into a bore therein or been embedd when casting the block. The plate or heat body is further provided with holes for the mounting bolts of the exhaust manifold. In the same way as in Fig. 2 the cavity or pipe 21 is maintained fill with water to a suitable level by means of the level control 5 (Fig. 1). The h exhaust gases discharged through the ports 20 of the plate heat the latter, a the heat is conducted through the material to the cavity 21 and heats the wat to generate steam. The generated steam leaves through one or both steam pip 23 (depending on the inclination of the vehicle). The steam pipes 23 are, in t same way as above, suitably connected to a water trap, from where t separated steam is sucked into the engine. Compared with, as in Fig. 2, placing pipe 15 within the exhaust manifold, no disturbance of the exhaust gas flow the manifold is obtained when using an insert plate according to Fig. 3. An alternative level control device is schematically indicated in Fig. Two moisture sensors 26 are each carried by T-connections 27 at the top side the horizontal sections of the two steam conduits 23, so that they project do into the continuation of the cavity 21 formed by the steam pipes. The sensors a preferably mounted to be vertically adjustable, e.g. by means of a screw devi (indicated by 29 in Fig. 3). The moisture sensors 26 may be of any convention type, such as those used for level controls, for leakage detection or the lik • Through a suitable circuit not shown t ey are arrange to actuate a so eno 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 5 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 0 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. 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 -5 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 0 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. - 5 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 correspon¬ dingly arranged steam inlets at the sides and steam and water outlets at the top 0 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 t roug t e tan . The steam supply system according to the invention is simple to mou particularly the embodiment of an insert place according to Figs. 3 and 4. I further very reliable and requires a minimum of maintenance. As mentio previously a fuel saving of about 25 to 35 % is obtained at normal operat conditions, while simultaneously the carbon monoxide content of the exha gases is reduced considerably and the engine is caused to run quieter. reduced fuel consumption obtained is illustrated by the results from a laborat test, which was performed with a Volvo B16 petrol engine converted to a mar design and with a Schenk brake test-bed, and shown in the Table below. A syst according to Fig. 1 was used, the steam generation member 7 being comprised a straight copper tube having a diameter of 15 mm and being arranged in exhaust manifold as in Fig. 2. The generated steam was fed to the air cleaner. Motor speed Fuel Water Torque Power Efficiency rpm. g ml Nm kW Without water vapour 3500 150 - 101,2 37,1 . 0,235 With water vapour 3500 150 35 92,8 34,0 0.,29 As appears from the Table above, an increase of the efficiency of ab 23% was obtained for a water vapour supply corresponding to about 25 % weight of the supplied fuel quantity. The test was performed at full spe performance, and an even greater increase of the efficiency would therefore expected for normal driving. This is confirmed by a test made with a devi according to the invention (Fig. 2) mounted in a passenger car. During ab 60,000 kilometers' driving a lowered fuel consumption from 0,097 1/km 0,065 1/km was obtained. Further, a reduction of the CO content of the exha gases of about 8 times was observed. The invention is, of course, not restricted to the above particula described and shown embodiments, but many modifications and variations possible within the scope of the subsequent claims. The engine or correspondi engine parts may, of course, already at the manufacture thereof be provided wi or adapted to the device of the invention. _ * . ' — "** - - ■ - ■ _-i

Claims: 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 heatin 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 0 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) 5 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 0 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 5 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 0 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 -5 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 n ets at e en e , on 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 sai means (5) for maintaining the predetermined liquid level in the chamber ( comprises liquid level sensing means (26) arranged to actuate control valv 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 lev sensing means (26) comprise at least one moisture sensor.

Applicants: ANDERSSON J
Application year: 1981
Main classification: F02M25
IPC codes: F02M25