GB2051234A

GB2051234A - Fuel injection valve with ducts for a supplementary fluid

Info

Publication number: GB2051234A
Application number: GB8017647A
Authority: GB
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1979-06-02
Filing date: 1980-05-29
Publication date: 1981-01-14
Also published as: DE2922682A1; FR2457984A1; IT1127480B; IT8048829A0

Abstract

The fuel valve 8 lifted by fuel fed to the chamber 4 exerts a pumping action on water or a gaseous fuel supplement supplied to the spring chamber 9 to discharge the supplementary fluid through ducts 10, 11, 12 in the valve. A non-return valve (20), Fig. 2 (not shown), in the valve 8 may prevent return fluid flow from an axial fluid discharge duct (18). <IMAGE>

Description

SPECIFICATION Fuel-injection nozzle The invention relates to a nozzle, for injecting fuel and a supplementary medium, particularly but not exclusively water, into a combustion chamber of an internal-combustion engine, comprising a pintle closing a discharge passage and opening by lifting from a valve seat against the closing force of a spring disposed in a spring chamber. The nozzle is intended especially for fuel injection into engines of air-compressing type.

The invention seeks, by simple means, to provide an injection nozzle of the aforesaid kind, especially for an air-compression, fuel-injection, engine, by which the fuel can be so injected into the combustion chamber together with a predetermined quantity of water that the emission of the nitric oxide from an internal-combustion engine with self-ignition can be considerably reduced.

According to the invention, a nozzle for injecting fuel and a supplementary medium into a combustion chamber of an internal combustion engine, particularly water into a combustion chamber of an air-compressing fuel-injection engine, comprises a pintle closing a discharge passage and opening, by lifting from a valve seat against the closing force of a spring disposed in a chamber in the nozzle, which spring chamber serves to accommodate the supplementary medium and acts as a pump pressure chamber and is connected by ducts in the pintle to the combustion chamber when the discharge passage is open.

In the nozzle according to the invention, the pintle is utilized to pump and to control the quantity of water injected into the combustion chamber. Depending upon the displacement volume of the pintle, a predetermined quantity of water is sprayed into the combustion chamber upon the lifting of the pintle from its valve seat and associated opening of the discharge passage or passages.

In comparison, with an injection nozzle known from German Specification O.S. No. 22 52 307, a pressure drop produced after closure of the pintle by the action of a non-return valve in the injection pump is utilized to supply the nozzle with water in the fuel-feed passage.

Embodiments of the invention by way of example will now be described more fully with reference to the accompanying drawing, in which: Fig. 1 is an axial section through part of a fuelinjection nozzle and water-supply device connected thereto, Fig. 2 is a similar section of a nozzle with a pintle of different construction from that of Fig. 1, and Fig. 3 is a similar section of a nozzle and a device for the supply of a gaseous fuel supplement connected thereto.

In each of the figures, a fuel-injection nozzle 1 of the kind having a pintle with a throttling spigot comprises a nozzle element 3 having a discharge or outlet passage 2, and a fuel-feed passage 5 opening into a fuel-accumulating chamber 4. The pintle 8 lifts from its conical valve seat 7 and opens the outlet passage 2 against the closing force of a nozzle spring 6. The spring 6 is arranged in a chamber 9 serving as a pump pressure chamber. When the passage 2 is open, the chamber 9 communicates through a central bore 10 and discharge bores with the combustion chamber 1 3 of an air-compression fuel-injection internal combustion engine.In Figs. 1 and 3, the discharge bores 11 and 1 2 are branched from the bore 10 and terminate opposite to the valve seat 7, where they are opened or closed by the pintle 8 depending upon its position.

Adjacent to the spring chamber 9, there is a device by which water is fed under low pressure from a supply vessel 14 by a feed pump 1 5 through a non-return valve 1 6 to the chamber 9.

Pumping of water into the combustion chamber 13 occurs, when the pintle 8 is lifted, by the displacement of a volume of water in the chamber 9 by a shoulder 1 7 on the pintle. The quantity of water thus injected depends upon the pintle crosssection and pintle stroke. Because the said stroke increases with increasing engine load, the desirable increase in the quantity of water with load occurs automatically.

By appropriate dimensioning of the diameter of the bores 11 and 12 (this also applies to the exemplary embodiment described hereinbelow) it is also possible to achieve a desirable reduction in the quantity of water injected at high speed. For this purpose, the diameter must be reduced to such an extent that the pintle 8, lifting rapidly at high engine speed, no longer sprays the whole of the displaced volume of water through the bores 11, 12, but compresses it in the chamber 9.

In the nozzle 1 of Fig. 2, a discharge bore 18 in the pintle spigot opens directly into the combustion chamber 1 3. Between the central bore 10 and bore 18, there is a valve chamber 19 with a spring-loaded valve 20 which prevents permanent inflow of water due to the pressure produced by the feed pump 1 5 (not shown in Fig.

2). In this case also, with appropriate design, reduction in the quantity of water injected at high speed can be achieved.

The injection nozzle 1 shown in Fig. 3 is similar to that of Fig. 1 except that the feed device comprises a pressure reservoir 21 for a gaseous fuel supplement and a pressure-regulating valve 22. This supplement is supplied to the chamber 9 and thence by the pumping action of the pintle 8, to the combustion chamber. Dosing of the fuel results from regulation of the feed pressure.

By virtue of the invention, it is possible in simple manner to feed to the combustion chamber in addition to the usual fuel, another liquid or gaseous medium which improves the behaviour of the engine in use. The operation of the nozzle with respect to the injection of the fuel may be conventional.

Claims

1. A nozzle, for injecting fuel and a supplementary medium into a combustion chamber of an internal-combustion engine, comprising a pintle closing a discharge passage and opening by lifting from a valve seat against the closing force of a spring disposed in a chamber in the nozzle, which spring chamber serves to accommodate the supplementary medium and acts as a pump pressure chamber and is connected by ducts in the pintle to the combustion chamber when the discharge passage is open.

2. A nozzle according to Claim 1, wherein the pintle has a central bore which extends from the spring chamber and from which branch two discharge bores opening opposite to the surface of the valve seat in the lower region of the pintle

3. A nozzle according to Claim 1 or 2, wherein, for a liquid supplementary medium, the said medium is fed under low pressure from a supply vessel by a feed pump through a non-return valve to the spring chamber.

4. A nozzle according to Claim 1 or 2, wherein, for a gaseous supplementary medium, the said medium is fed from a pressure supply vessel through a pressure-regulating valve to the spring chamber.

5. A nozzle according to Claim 3, wherein the pintle has a central bore which extends from the spring chamber and opens into a valve chamber, whence extends a discharge passage for communicating with the combustion chamber, a valve being provided in the valve chamber for closing the central bore when the pintle is not pumping.

6. A fuel-injection nozzle substantially as hereinbefore described with reference to Fig. 1, Fig. 2 or Fig. 3 of the accompanying drawing.