The invention relates to a method in a combustion engine process operating by a piston or the like in a cylinder space or the like, wherein a medium combina¬ tion is fed into the cylinder space at least for inducing combustion and preferably also for increasing the efficiency of the combustion engine process.

The present invention is closely but not solely related to combustion engine processes with ignition by compression, particularly the so-called diesel process. In a combustion engine process with ignition by compression, fuel is injected at the beginning of the working phase to the combustion gas compressed to a high pressure by the piston in the cylinder space. Injection of fuel into the cylinder space under a high pressure is problematic in many respects. First of all, the injection of the fuel must take place at precisely defined points of time, synchronised with the movements of the piston. The injection of the fuel is particularly problematic when, for producing a pressure in the fuel to be injected, pumps are used which operate by the principle of positive displace¬ ment, because a circulation arrangement must be provided for the pressurized fuel. Further, the displacement pump arrangement results in continuous pressure strokes in the fuel distribution line and in the return line, thus making the construction vul¬ nerable to disturbances and also reducing its service life. For these reasons, attempts have been made to eliminate disadvantages of injection systems based on the displacement pump principle, and in this respect reference is made to US-4,421,088. This publication discloses a two-phase pump arrangement which recharges the distributing pressure accumulator unit with high- pressure fuel used for injection. The system improves

the injection of fuel in relation to the displacement pump solution particularly because it requires no fuel circulation arrangement; however, the construction itself, because of the two-phase pressure-raising arrangement and the distributing pressure accumulator unit in connection therewith, is complex and vulnerable to disturbances.

Further, reference is made to DE-285844, DE-400446 and DE-3132872 as publications of prior art. From these publications, blow arrangements are known which are used to transfer a gaseous medium to the combustion process.

It is the aim of the present invention to present an improved method for combustion engine processes, whereby a combination of liquid mediun is fed into the cylinder space, at least fuel and possibly also a liquid medium increasing the efficiency of the combus- tion engine process or active in the process or effective in the combustion result in another way. Thus, the main purpose of the invention is to raise the state of art in the field, whereby the method can be used to secure the continuous action of the combus- tion engine process with no disturbances. For achieving this aim, the method of the invention is primarily characterized in that a kinetic pump is used in connection with the work stage in feeding at least one liquid medium of the medium combination. By adjusting the pressure level of the kinetic pump to correspond to the pressure level required in the combustion engine process at the time of feeding, the liquid medium can be fed by very simple control operations. At the same time, the disadvantages of known techniques are avoided. By using a kinetic pump in the feeding of at least one liquid medium, an impulse-free fuel injection which is easily controlled with respect to time, is achieved without pressure

accumulators. Further, pressure strokes caused in the medium injection system are insignificant, because they are only caused at the stage when the means for controlling the injection of the medium is closed. The control system required for maintaining the pressure of the liquid medium is simple.

According to an advantageous embodiment, the method of the invention is characterized in that the liquid medium is fed into the cylinder space at least during the operational stage in a way that the control system in connection with the combustion engine process is used to open the on/off valve means between the kinetic pump and the cylinder space. By this technical solution related to the method, it ^' is possible to use a kinetic pump particularly in combustion engine processes operating on the compression-ignition principle.

Further according to an advantageous embodiment, the method of the invention is characterized in that the power source of the kinetic pump is a gaseous medium, preferably a gaseous medium used and/or produced in the combustion engine process. This technical solution related to the method makes it possible to achieve a compact total combustion engine process with a tech¬ nically advantageous energy solution.

In the embodiments of the method using compressed combustion air, it is advantageous that part of the compressed air is led to the driving unit of the kinetic pump to be used as the power source of the kinetic pump. Particularly in compressed combustion engine processes, the dimensions of the compressor unit can be arranged in a way that part of the com- pressed air can be used as the power source of the kinetic pump in addition to the fact that part, most often a major part, of the compressed air is used as

the combustion air of the combustion engine process, particularly in processes with ignition by compression.

Particularly in compressed combustion engine processes, the power source of the kinetic pump can be exhaust gases of the combustion engine process instead of, or in addition to, compressed air. This option is one alternative in the design of a combustion engine process applying the method of the invention.

When a gaseous medium is used as a power source of the kinetic pump, one advantageous embodiment is that at least one turbine unit is arranged in a transmission connection with the kinetic pump, through which unit the said gaseous medium is conveyed.

In some embodiments of the method, it is naturally possible and advantageous to use an electric motor as the power source of the kinetic pump.

Particularly in combustion engine processes using compressed combustion air, several technical solutions comprise a turbine unit utilizing a gaseous medium, particularly exhaust gases, obtained from the co bus- tion engine process, whereby the compressor and turbine units are provided on a common shaft. In some embodi¬ ments of the method according to the invention, it is advantageous to place the kinetic pump coaxially with the common shaft of said compressor and turbine units. This solution provides a particularly compact arrange¬ ment for feeding the medium.

As mentioned above, one particularly advantageous liquid medium for use in the method is diesel oil used in the diesel process. In the same way, the method of the invention can be applied in the Otto process, whereby said at least one liquid medium fed into the cylinder space is a mixture of gasoline

and/or corresponding fuel suitable for the Otto-cycle engine process.

According to an advantageous embodiment of the method of the invention, which can be used as an alternative for feeding fuel in both diesel and Otto processes, or in addition thereto, the said at least one fluid medium used for feeding into the cylinder space is at least one medium making the combustion engine process more effective, particularly by limiting the exhaust gas emissions, such as nitrogen oxide emissions. Particularly in combustion engine processes based on ignition by compression, such as in the diesel process, one difficult problem has been the high nitrogen oxide (N0 _χ ) contents of the exhaust gases. By the method of the invention, it is possible to provide separate injection of additives reducing nitrogen oxide emissions, particularly at the beginning of and/or during the operation, to increase the efficiency of the combustion process and thus to reduce the exhaust gas emissions. It is obvious that the method of the invention can also be applied in the feeding of other media used in the combustion engine process.

Further according to an advantageous embodiment, the kinetic pump used is a centrifugal pump and/or a pump driven on Pitot's principle. In this invention, the kinetic pump refers in general to a non-displacement pump. This kind of a pump is characterized in that its pressure side can be compressed during its opera¬ tion, and it can even be closed without damage to the pump or a need for an internal by-pass circulation during throttling or closing. To provide the pressure level required in the method, the pump functioning on the kinetic principle and/or the actuator on the same shaft must have a very high rotational speed, e.g. more than 10 000 rpm.

Some advantageous embodiments of the method according to the invention are presented in the other appended claims related to the method.

The invention will be described in more detail in the following description with reference to the embodiments shown in the appended drawings. In the drawings,

Fig. 1 shows schematically the main principle of the method according to the invention, and

Figs. 2—4 show also schematically some advantageous embodiments of the method according to the method. ^' '

Figure 1 shows schematically the main principle of the method according to the invention. The structure shown in Fig. 1 comprises two cylinders la, lb with each a piston 3a, 3b moving in the cylinder spaces 2a, 2b. In Fig. 1, the left piston 3a is beginning the work stage and still moving upwards at the beginning of ignition by compression, and the right piston 3b is moving downwards at the end of the work stage. The cylinder spaces 2a, 2b are coupled with a fuel feeding arrangement 4 comprising valve means 5a, 5b connected to both cylinders, particularly injection nozzles operating on the electromagnetic principle. The valve means 5a, 5b comprise nozzle heads, through which a fluid medium is injected to the respective cylinder space 2a or 2b. The valve means 5a, 5b are connected by means of a tubing or the like 6 to a kinetic pump 7 coupled with an actuator 8. The kinetic pump 7 is further connected by a tubing 6 to a tank 9 of the fuel to be injected. The fuel feeding arrangement 4 comprises also a control system 10 controlling e.g. by means of an electric or corresponding control 11 the opening and closing of the valve means 5a, 5b in a synchronized manner by the on-off principle so that

the injection (cylinder space 2a) takes place at the beginning of or during the operational stage, as shown by lines 12 in Fig. 1. As shown in Fig. 1, the kinetic pump, particularly a centrifugal pump and/or a pump driven on Pitot's principle, does not require a separate circulation arrangement, and the system will operate even though both valve means are some¬ times closed simultaneously. The actuator 8 can be e.g. an electric alternating- or direct-current motor, as shown in Fig. 1. Other alternative actuator arrange¬ ments are shown particularly in the appended Figs. 2 to 4. The fuel feeding arrangement 4 is in the embodi¬ ment of Fig. l intended particularly for injection of diesel oil.

Figure 2 shows an embodiment of the method according to the invention, using combustion air compressed in a combustion engine process on the principle of igni¬ tion by compression, particularly in a diesel process. For this purpose, a shaft 13 provided with bearings 12 and coupled with a compressor unit 14 and a turbine unit 15, is arranged in connection with the cylinder 1, the cylinder space 2 and the piston 3. The compressor unit 14 is connected by a main line 16 to the cylinder space 2 for feeding the combustion air to the cylinder space. As already described above in connection with Fig. 1, the cylinder 1 is equipped with a valve means 5, a tubing 6 as well as a control system 10, by which the injection of the diesel fuel into the cylinder space 2 is arranged in this embodiment e.g. by an arrangement of Fig. 1. In the embodiment shown in Fig. 2, the fuel feeding arrangement 4 is par¬ ticularly provided with a kinetic pump 7 for additional injection of a medium for making the combustion engine process more effective. The medium injected by the kinetic pump 7 can be particularly an additive for reducing nitrogen oxide emissions. The additive is fed by the kinetic pump via the feeding line 17 to

the cylinder space 2. Between the cylinder space 2 and the kinetic pump 7, the feeding line 17 is provided with a valve means 18, opened and closed by a control arrangement 10 in a manner that the injection of the medium into the cylinder space 2 takes place in a synchronized manner, particularly so that the medium is injected into the cylinder space 2 during the work stage. The second valve means 18 can be an electrically controlled valve means operating by the on-off prin- ciple, particularly an electromagnetic valve which is controlled by the control system 10 via an electric control line 19. It should be noted that the two extended lines shown in Fig. 2 by three broken lines extending from the control system 10 illustrate the possibility of synchronized control by the control system of the engine, in this case with four cylinders (broken lines 11' and 19').

The power source of the actuator 8 is part of the compressed combustion air produced by the compressor unit 14. The main line 16 is provided with a tapping line 20, whereby part of the compressed combustion air is conveyed to the second turbine unit 21 in the actuator 8, connected by bearings 22 and a shaft 23 for use as the driving unit of the kinetic pump. The tapping line 20 is provided with e.g. an electromotor- controlled control valve 24, whereby the efficiency of the second turbine unit can be controlled.

The turbine unit 15, on the other hand, is connected to the exhaust gas outlet 28, and the exhaust gas outlet 28 is further connected after the turbine unit 15 to the outlet 25 of the second turbine unit 21.

The above arrangement is very simple in construction, particularly in cases where compressed combustion air is used. It is obvious that although the embodiment of Fig. 2 is described only in terms of injection of

a medium for increasing the efficiency of the combus¬ tion engine process, it is also possible to use a turbine unit in a similar way as the driving means of the kinetic pump for injection of the fuel by valve means 5 so that the power source is part of the compressed air produced by the compressor unit.

Further with reference to Fig. 3, in one embodiment of the method according to the invention the actuator 8 (Fig. 1) comprises a third turbine unit 29 using exhaust gas as the power source. A tapping line 30 is formed in the exhaust gas outlet 28. In other respects, the embodiment shown in Fig. 3 corresponds substan¬ tially to the embodiment of Fig. 2. Also in this embodiment, the tapping line 30 can be equipped with a valve corresponding with the valve 24 of Fig. 2 as well as with an arrangement corresponding to the actuator unit 26 and the connector means 27. These alternatives, being part of the know-how of a profes- sional in the field, are omitted in this context for simplifying the schematic view. In the embodiment of Fig. 3, the kinetic pump 7 is arranged to inject a medium for increasing the efficiency of the combustion engine process into the cylinder space 2.

Moreover, Fig. 4 shows another embodiment of the method according to the invention, whereby the kinetic pump 7 is placed coaxially (shaft 31) with the common shaft 13 of the compressor unit 14 and the turbine unit 15. The kinetic pump 7, which is provided in duplicate, is in this context intended for use as a fuel injection pump 7a on one hand and as a pump 7b for injecting a medium for increasing the effiency of the combustion engine process on the other hand. In other respects, the reference numbers in Fig. 4 cor¬ respond particularly to the reference numbers of Figs. 1 and 2. In some embodiments, it is probably most advantageous for the start-up of the combustion

engine process to provide the shaft 13 with an electric motor or with a coupling for coupling an electric motor with the shaft 13.

It is obvious that the method of the invention can be modified within the scope of the basic idea even to a considerable degree, particularly by combining the single solutions shown in Figs. 1 to 4 into a combina¬ tion needed for each use. Particularly in a case when a gaseous medium used and/or produced in the combustion engine process is used as the power source of the actuator 8 upon feeding fuel into the combustion engine process, the combination of the kinetic pump 7 and the actuator 8 must be provided with a separate actuator unit 26, such as an electric motor (shown by broken lines in Fig. 2 ) , for use particularly at starting up the combustion engine process. One par¬ ticular advantage of the method is the fact that the apparatus for applying the method can be constructed so that the leakages from the mechanical outlets remain within the process; in other words, e.g. the sealings of the driving shaft of the pump leak through the shaft space to the turbine space and from there out through the normal outlet of the process. Conse- quently, there are no leaks in the machine space.