Internal combustion engine comprising a fuel injection nozzle with an additional supply of a combustion-promoting medium into the combustion chamber

Abstract

A reciprocating piston-type internal combustion engine includes a cylinder head that has an inlet valve that can be supplied with combustion air from a cylinder inlet line connected to the inlet valve, comprising a pressure accumulator, out of which an additional medium that promotes the combustion in the cylinder can be supplied to the cylinder in a controlled manner, and an injection nozzle, via which fuel can be injected into the cylinder. The additional medium is a combustion air/fuel mixture according to the invention. The pressure accumulator is connected to the injection nozzle which has a nozzle needle, and the additional medium can be introduced into the cylinder in a controlled manner by means of the injection nozzle.

Claims

1. A method for introducing an additional medium which promotes combustion in the cylinder of a reciprocating piston-type internal combustion engine into the cylinder of a piston-type engine, wherein the cylinder head has an injection nozzle with a nozzle needle, and wherein the medium is supplied via the injection nozzle of the piston-type engine, characterized in that the additional medium is a combustion air/fuel mixture which is taken from a pressure accumulator and introduced into the cylinder via the injection nozzle which supplies the fuel.

2. The method according to claim 1, characterized in that the medium is supplied at least partially at the same time as the fuel is supplied to the cylinder.

3. The method according to claim 1, characterized in that the medium is supplied by valve control, independently of the lifting movement of the nozzle needle of the injection nozzle.

4. The method according to any one of the claim 1, characterized in that the additional medium is introduced during the fuel injection by lift control.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, details and embodiments of the invention will now be described in detail with reference to the embodiment explained below in the drawings. In the drawings:

(2) FIG. 1 shows a schematic view of a cylinder of a reciprocating piston-type engine having an intake passage, an exhaust pipe, and pressure vessel connected to the injection nozzle for a medium for promoting combustion in the cylinder;

(3) FIG. 2 shows a sectional view through the cylinder of a reciprocating piston-type engine having an intake valve, exhaust valve and injection nozzle;

(4) FIG. 3 shows a sectional view through an injection nozzle designed as a throttle pin nozzle on the cylinder head, with a supply line for a medium which promotes combustion in the cylinder;

(5) FIG. 4 shows a view according to FIG. 3, but with an open sealing seat of the nozzle needle in the lifted position thereof;

(6) FIG. 5 shows an enlarged detail view of a throttle pin nozzle as an injection nozzle; and

(7) FIG. 6 shows a blind hole nozzle as an injection nozzle, with larger (left) and smaller blind hole (right).

DETAILED DESCRIPTION

(8) FIG. 1 is a schematic view of a cylinder 2 of a reciprocating piston-type engine with an intake valve 3 and an exhaust valve 11 mounted in the cylinder head 1. Via a charge air line 4 and/or an intake passage, inlet air 15 is passed through a compressor 25 to increase the boost pressure, and from there to the intake valve 3 and, if the intake valve 3 is open, is guided into the cylinder 2. When the exhaust valve 11 is open, burnt gas 16 flows after combustion through the exhaust valve 11 into the exhaust pipe 12, and from there through the exhaust gas turbine 26 where energy is extracted from the exhaust gas 16 to drive the compressor 25 arranged in the intake passage 4.

(9) In addition, an injection nozzle 7, via which fuel is injected into the cylinder for combustion via a fuel line 24, is arranged in the cylinder head 1. A medium line 13 for a gaseous or liquid medium is connected to the injection nozzle 7, the medium being introduced via the injection nozzle 7, specifically via the interior of the injection nozzle 7 through the nozzle needle 6, into the cylinder 2 to promote the combustion. The gaseous or liquid medium may be combustion air, the oxygen content of which contributes to improved combustion, or a combustion gas that ignites and burns solely at the temperatures created by the compression in the cylinder 2 as the piston 20 moves toward top dead center, such that additional energy is provided for the power stroke of the piston 20 of the internal combustion engine. The work resulting from the combustion is forwarded via the piston 20, the crankpin 19, and the connecting rod 18 to drive the crankshaft, which is not shown in FIG. 1.

(10) A pressure accumulator 5 for the medium is connected to the medium line 13 and thus to the injection nozzle 7. Between the pressure accumulator 5 and the injection nozzle 7, a valve 10 is arranged via which the amount of pressurized medium is supplied via the injection nozzle 7 to the cylinder 2 for improved combustion. This valve 10 is controlled via a control device 21 to control the amount of medium passed through it. The control is carried out according to desired and/or monitored engine parameters, such as cold start behavior, performance, emissions, etc.

(11) FIG. 2 shows a cross-section through a reciprocating cylinder. The cylinder 2 has a cylinder head 1, in which an intake valve 3, an outlet valve 11, and an injection nozzle 7 are arranged. Intake air 15 flows via an intake passage 4 to the intake valve 3 and, upon its opening during the purging and/or intake stroke, into the cylinder 2. In the cylinder 2, a piston 20 is guided in the cylinder liner 17, and is connected via a crankpin 19 and the connecting rod 18 to a crankshaft, which is not shown. An exhaust valve 11 is also arranged in the cylinder head 1, which in the opened state passes burnt gas resulting from the combustion process in the cylinder 2 into the exhaust pipe 12 as exhaust gas 16, which is conveyed in its further coursefor example, to an optionally present exhaust gas turbine 26 (see FIG. 1). FIG. 2 shows the basic structure of such a cylinder 2, without the connection line for the pressurized medium on the injection nozzle 7.

(12) This can be seen from the detailed drawing according to FIG. 3. FIG. 3 shows a schematic representation as a sectional view of an injection nozzle 7 in a cylinder head 1 of a cylinder 2, with a nozzle needle 6 in its interior in the conventional, known construction. The injection nozzle 7 is designed as a throttle pin nozzle and therefore has only a single sealing seat 8 and a single injection orifice. The advantage of such throttle pin nozzles is that a certain degree of self-cleaning during the combustion process in the cylinder 2 is possible due to there only being one injection orifice. This sealing seat 8 is arranged at the lower point region of the nozzle needle 6. In the interior of the nozzle needle 6, a medium channel 9 is provided via which the combustion-promoting medium is introduced into the cylinder 2. This bore is arranged in the longitudinal direction, and expediently coincides with the longitudinal axis of the nozzle needle 6. In addition, this nozzle needle 6 has radially extending bores which are connected to a supply line in accordance with position, wherein the cross-section width of the supply line for the medium as taken in the longitudinal direction of the nozzle needle 6 is large enough that the medium is applied to the radial bores of the nozzle needle 6 in its stroke region. In order to ensure an improved supply of the medium, a distributor groove, which is not shown separately in the figure, which runs peripherally, is provided on the nozzle needle 6 and/or on the injection nozzle 7. This corresponds in width to the diameter of the respectively assigned supply bore. This groove is configured on the outer diameter of the nozzle needle 6 and/or on the inner diameter of the injection nozzle 7, which serves to receive the nozzle needle 6. The medium is supplied via a medium line 13 via a connection plug to the nozzle needle 6 in the interior of the injection nozzle 7. In the medium line 13 there is, between the pressure vessel for the medium (not shown in FIG. 3), a valve 10, whose closing and opening operation is controlled by a control device 21 according to engine parameters such as operating characteristics, performance, cold start behavior, and emission behavior. Inside the injection nozzle 7, there is a fuel line 24, by means of which the fuel is conveyed into the injection nozzle 7 and thus into the lower region of the nozzle needle 6. With appropriate application, this fuel is conveyed into the region of the nozzle which has a frusto-conical seat 8, by means of which by nozzle needle 6 is lifted off the same by the fuel pressure by the effect of its resulting compressive forces in the direction of the longitudinal axis.

(13) The lifted state of the nozzle needle 6, in which the sealing seat 8 is opened at the tip of the nozzle needle 6, is shown in FIG. 4. The other components correspond to those in FIG. 3, such that they will not be explained again in more detail.

(14) For better understanding, two basic types of injection nozzles are shown in enlarged view in FIG. 5 and FIG. 6namely a throttle pin nozzle according to FIG. 5, as has already been described in connection with FIGS. 3 and 4, and a blind hole nozzle according to FIG. 6, which also is used in an arrangement according to FIG. 3 or FIG. 4 in the injection nozzle 7.

(15) According to FIG. 5, the nozzle needle 6 is guided to the sealing seat 8 by a pin tip with its sealing area, such that, due to the pressing force of the fuel acting on the nozzle needle 6, the nozzle needle lifts off of the sealing seat 8 and fuel is supplied through the fuel line 24 into the lower region of the nozzle needle 6. The lower region is frusto-conical and is subjected to a force acting in the direction of the longitudinal axis of the nozzle needle 6 when fuel pressure is present and/or prevailing. The fuel pressure must at this point be high enough that the resulting force acting on the nozzle needle 6 is sufficiently large to lift it off of its seat in the injection nozzle 7.

(16) In its basic function, the blind hole nozzle does not differ from the throttle pin nozzle, except that below the sealing seat 8 of the nozzle needle 6 in the injection nozzles 7, a blind hole 22 is formed, which realizes, after the lifting of the nozzle needle 6 due to the presence of fuel, a release of the sealing seat 8 such that, under these circumstances, pressurized fuel conveyed from the fuel line 24 into the blind hole 22 is conveyed in the radial injection bores 23 to the cylinder 2 and introduced there in atomized form. The combustion-promoting medium can then be supplied through the inner bore 9, which is not shown in FIGS. 5 and 6, via the controllable valve 10.

(17) Depending on various engine parameters, the control of the release of the sealing seat 8 can be such that at defined times the fuel and the medium can be injected and/or introduced into the cylinder 2.