The present invention concerns a device at internal combustion engines with an inlet valve provided in its inlet port, and which device is of the type incorporating means for supplying at least one fluid, which can be the fuel for running the engine, or a fluid other than the fuel, and which means consists of a feeding line with its mouthpice directed towards the combustion chamber, whereby at least the portion around the outlet opening of the feeding line is surrounded by a line for a gaseous medium, having a pressure different from that prevailing outside the mouthpiece.

BACKGROUND OF THE INVENTION

Injection of smaller amounts of water, or water and an antifreezing agent in the purpose of having the possibility of using a plurality of fuels of different octane rating, or mixtures thereof, at unchanged compression ratio, as described in Swedish patent 8ip6113, has proven itself to be successful and has a positive influence on the efficiency. It has been experienced that the atomization of the fluid is very important. The injection valves available on the market are rather complicated, and there are problems in using them. In addition they dont stand corrosive luids, and they have a tendency to stick as a result of the combustion gases. If the opening of the injection valve is made wider it is difficult to atomize the fluid, particulary under low-load conditions.

According to a known fuel injection system ( DE- 1.933.51 -A1 ) the atomization of the fuel is certainly supported, but if for different reasons - the supplied fluid has to be led directly to the inlet opening of the combustion chamber, the continuously operating injection valves are so big, that they disturb the air stream if they are arranged close to the inlet valve, with desired injection direction. If the injection valves on the other hand are located so that the air stream is not disturbed, an incorrect injection angle is obtained. The problems increase dramatically if the injection valve is

surrounded by an additional mantle. Another alternative, suggested in the German publication, is to let the fluid, which has left the atomizer and become atomized, be conveyed in a tube, possibly provided with means for preheating. This means with necessity that the atomization of the fuel is rendered- more difficult, particulary if the fluid used is water and or alcohol. The problem of the hitherto known technique is that it is not possible to have a continuous injection in close vicinity of the inlet valve without disturbing the air flow, obtaining incorrect alignment of the atomizer or deteriorating the atomization. Further there is another practical problem at known continuous injection valves _r i.e. that they get stuck if they have been run with water and or alcohol, and must be cleaned after each stop that lasts for a longer period (some hours). It is further of essential importance that the atomization of the fluid is not effected to early, but just before the fluid is sucked into the combustion chamber. According to said German publication there is brought about an admixing of the fuel and the air on the way to the inlet opening, i.e. the opposite effect is obtained .

THE PURPOSE AND HOST ESSENTIAL FEATURES OF THE -INVENTION

The purpose of the present invention is to provide a very simple device for atomization also of small liquid quantities at injection into a cylinder, which at the moment is in its suction stroke. This has been achieved in that the outlet opening of the supply line and of the medium line are arranged in close vicinity of one another and in close vicinity of the suction opening of the combustion chamber formed by the inlet valve.

DESCRIPTION OF THE DRAWINGS

The invention hereinafter will be further described with reference to accompanying drawings, which show some embodiments.

Fig. 1 shows a vertical section which through a portion of the cylinder head at an inlet valve of a combustion engine. Fig. 2 is a section along line II-II in Fig. 1.

Fig. 3-6 show in bigger scale, sections through different embodiments of the front end portion of the supply line.

DESCRIPTION OF EMBODIMENTS

In fig. 1 and 2 11 denotes a cylinder head of a combustion engine, 12 an inlet channel of the combustion chamber 13 of the engine cylinder and an inlet valve 14- , which cooperates with a valve seat 15. 16 denotes the exhaust channel of the cylinder and 17 the outlet valve.

Through a bore 18 in the inlet channel 12 is introduced in the cylinder head 11 a supply line 19 for a luid, e.g. water, which e.g. may be admixed with an antifreezing agent. The supply line 19 is surrounded by and spaced from a second line 20 for a gaseous medium, which has a pressure deviating from the pressure prevailing at the orifice 21 of the supply line, which is situated in close vicinity of the inlet valve 14, but which could possible open directly in the combustion chambers of the engine. The medium may be atmospheric air, in whichs case the line 20 is arranged thus that it communicates with the atmosphere outside the engine block. The medium may also be engine exhaust gases which under pressure are pressed through the medium line 20. The medium can also be a pressurized gas, e.g. a small amount of air taken from a turbo charger. ■_

As can be seen from Figs 3 - 6 the end portions of the two lines 19 and 20 can be designed in different manners.

One of the lines is preferably provided inside the other line in such a way that an annular channel is formed for the fluid and the medium, resp. It has proven itself that the shape of the mouthpiece is of great importance for the atomization of the fluid in the medium, and for this purpose it may be feasible to design the mouthpiece as shown in Fig. 3, i.e.

where the common outlet opening 22 of the supply line 19 and the medium line 20 has a smaller diameter than the inner opening 24 of the supply line 19.

For some applications it may be satisfactory that the fluid or the fluid droplets are carried along by the passing gas flow and in such cases the embodiment shown in fig. 4 may be used, where the orifice 24 of the supply line is axially displaced in relation to the orifice of the medium line 20. It thus may be situated outside the orifice 22 of the medium line, but it also can be positioned inside said orifice.

In Fig. 5 is shown a modification of the end portions shown in Fig. 3. which end portion is provided with a flanged out opening 22, in order to control the dispersion after the constricted passage, in which an efficient admixing of the fluid in the medium takes place.

In some applications it is desireable to add other fuels to the ordinary fuel, for example ethanol, and this fuel quantity may e.g. be supplied through a line 23 positioned outside the ^" supply line 19, but inside the medium line 20, as shown in fig. 6.

The flow control of the fuel is carried through with a dosing device at a distance from the combustion chamber sufficient not to influence the flow control device. As a result of this the demands on the flow control device are reduced whereby the conventional fuel valve can be disposed of, when the pressure at the orifice of the supply line varies less than in the inlet manifold. As the fluid is supplied under almost pressure-less condition and in very small amounts, the gas stream is necessary for carrying along and atomizating the fluid, whereby also the spray pattern can be varied automatically in accordance with the engine load.

The invention is not limited to the embodiments shown but a plurality of variations are possible within the claims. It is thus possible that more than one supply line with surrondiπg

medium line 20 is provided for each cylinder, whereby the single supply line can be the ordinary fuel line for each cylinder. The location of the supply line can be made in any optimal position, even e.g. in an intermediate flange betwen the engine block and the inlet manifold, whereas the position of the orifice is of big importance such as also shown in our older Swedish paten ^' t No 8106113.