Deutsche Forschungs- Und Versuchsanstalt Fur Luft- Und Raumfahrt E.v.

Klaus Baumer

Herbert Wiegand

Klaus Rath

Heinz D Distelrath

The injection device has a nozzle body with a needle valve controlled by id. At the front end of the nozzle body there are, in the case of a single hole nozzle, one injection channel and in the case of a multi-hole nozzle, several injection channels which may be at any angle to each other. In the narrowest cross section of the injection channel suction slots lead into the combustion chamber. Air is drawn in from the combustion chamber by the jet of fuel leaving the injection channel. This air mixes with the fuel in the narrowest cross section of the injection channel so that, at the base of the injection jet, there is a two-phase flow having particularly favorable properties for the subsequent mixture formation.

Injection device, more particularly for direct-injection diesel engines

In the ignition and starting phase of a high pressure combustion chamber device enables the flow velocity in the combustion pipe of the combustion chamber (21) to be reduced by the blocking air injected in counterflow through a slot nozzle in the narrowest cross section at the combustion chamber outlet (17) to such an extent that it is less than the flame propagation velocity. Owing to the fact that an adjustable throttle aperture (18) is fitted in the starting air line (16), during the starting process the pressure of the air jet issuing from the combustion chamber (21) is always less than the blocking air flow. As soon as a combustion chamber outlet temperature which can be associated with a stable state of operation in the combustion chamber (21) is measured on the temperature sensor (22), the drive (12) for the valve (11) is put into operation by means of a temperature-dependent switch-over device (23), which drive isolates the starting air line (16) and the blocking air line (15) from the air line ( 10) and connects this with the operating air line (20), and, because the valve (11) is designed with negative overlap, the air supply to the combustion chamber (21) is not interrupted.

Starting aid device for a high pressure combustion chamber

The injection device has a nozzle body (10) wherein the liquid-controlled edle valves (17; 18) are opened by the diesel fuel supplied by an injection pump via the annular line (12) and the pressure channels (13; 14) when the opening pressure p.sub.o, which is set at the pressure springs (19; 20) by way of the pressure adjusting discs (21; 22), is reached. In this connection the two needle valves (17; 18) can be opened and closed at different times within certain limits so that at a relatively low opening pressure p.sub.o for the needle valve (17) relative to the needle valve (18) the diesel fuel issuing through the spray aperture (24) into the combustion chamber (25) serves during the entire injection period as ignition jet for the alcohol fuel issuing from one or more spray apertures (29). The alcohol fuel, which is supplied continuously by a gear pump, flows from the pressure channel (26) to the collecting chamber (27) from where, interrupted by the liquid-controlled needle valve (18), it is injected intermittently via the blind hole (28) and the spray aperture(s) (29) into the combustion chamber (25). Due to the intake of air in the narrowest cross section of the spray apertures (24; 29), diesel and alcohol fuel arrive at the combustion chamber (15) already as two-phase mixture.

Injection device for direct injection diesel engines using alcohol and

According to the method in the two-fuel system, using diesel and alcohol l, the alcohol fuel is continuously supplied with a fuel pump and the diesel fuel is discontinuously supplied with an injection pump by way of separate lines of an injection apparatus. An apparatus, which is suitable for carrying out the method, has a nozzle body (10) with the fluid-controlled needle valves (17; 18a; 18b) which are operated after the opening pressure p.sub.o, which is adjusted at the pressure springs (19; 20a; 20b), is reached by the diesel fuel conveyed through the ring conduit (12) and the pressure channels (13; 14a; 14b), in which case the opening pressure p.sub.o for the needle valve (17) is constantly adjusted to a lower value in respect of the satellite needle valves (18a; 18b). After the needle valve (17) has opened, the diesel fuel, which is under high pressure, flows through the spray apertures (24a; 24b), from which the alcohol fuel, which is conveyed by way of the ring channel (27) and the inlet channels (28a; 28b), is entrained by the diesel fuel according to the Venturi-ejector principle and a two-fuel mixture develops in the spray apertures (24a; 24b). The apparatus can also be equipped with suction slots (31a; 31b) which open out in the narrowest cross section of the spray apertures (24a; 24b) so that by sucking in air out of the combustion chamber (25) a two-fuel two-phase flow develops there.

Growing community of inventors

Bonn, Germany

Klaus Baumer