FI113684B - Fuel Injection Valve And Method In Fuel Injection - Google Patents

Abstract

A fuel injection valve comprising a needle valve assembly (2) arranged in a valve body (1), where a valve needle (2') is arranged to control the fuel injection into a cylinder (11) of an engine from a fuel chamber (5) arranged in the valve body (1). The fuel injection valve comprises a pressure sensing chamber (6) arranged in communication with the fuel chamber (5) and pressure measuring means (7) are arranged in communication with the pressure sensing chamber (6). The invention also relates to a method for fuel injection, wherein fuel is conducted at raised pressure, controlled by a valve needle (2') arranged in the valve body (1) from a fuel chamber (5) to a cylinder (11) of an engine, and wherein fuel is conducted from the fuel chamber (5) at raised pressure via pressure reducing means (9) arranged in the valve body to the pressure sensing chamber (6), where pressure measuring means (7) are arranged to monitor the operation of the injection valve.

Description

FUEL INJECTION VALVE AND METHOD FOR FUEL

IN SPRAY - INSPRUTNINGSVENTIL FÖR BRÄNSLE OCH FÖRFA-

RANDE VID BRÄNSLEINSPRUTNING

The present invention relates to a fuel injection valve according to the preamble of claim 1 and to a method of fuel injection according to the preamble of claim 7.

Injection of fuel is commonly used in the so-called. needle valves for the purpose of understanding valves commonly used in the art, wherein the valve body 10 is elongated and thin. In particular, fuel-injection systems based on common-stock storage have become more common and, for example, heavy oil can be used as fuel. Especially in the aforementioned common-rail fuel supply systems, it is very important that the injection event is well controlled. In order to ensure operational safety, it is also essential that the initiation of the injection and combustion process can be effectively controlled.

One common rail injection system is described in EP 959 245, in which connection the present invention can be successfully applied and thus improve the system disclosed herein. In such a system, there is a constant pressure in the one-to-twenty high pressure reservoir, whereby a possible malfunction of the injection valve may cause fuel leakage to the cylinder.

The object of the present invention is to provide a new fuel injection valve and a method for fuel injection. In particular, it is an object of the present invention to provide a novel injection valve arrangement for use, particularly in a piston engine based common rail pressure storage system, that is reliable in providing greater control and monitoring of the injection event and thereby the combustion event.

The objects of the invention are mainly achieved in the manner detailed in claims 1 and 7 and in the other claims.

2, 113684

The fuel injection valve of the present invention comprises a needle valve assembly mounted on a valve body and fitted with a valve needle to direct injection of fuel into the engine cylinder from a fuel chamber mounted on the valve body. The injection valve further comprises a fuel pressure gauge-5 backing chamber adapted to cooperate with the needle valve assembly fuel chamber and a pressure gauge means adapted to cooperate with the pressure gauge chamber. The invention is characterized in that the pressure measuring chamber is arranged to cooperate with the fuel chamber through the first pressure relief means, whereby the pressure in the pressure measuring chamber 10 can be lowered to a level suitable for measuring the pressure. The pressure gauge chamber is further communicating with the fuel return duct to drain the outgoing fuel from the injection valve, allowing the fuel to flow out of the gauge chamber as needed.

A non-return valve or the like is provided between the pressure measuring chamber and the first pressure relief means. Correspondingly, other pressure relief means are disposed between the pressure measurement chamber and the fuel return duct. The pressure relief members generally comprise a bore, nozzle, flange or the like of a suitable size. In particular, the first pressure relief members consist of a replaceable nozzle body or the like, provided with a hole of a suitable size to achieve the desired pressure drop.

In the method of fuel injection, the fuel is: · fed under elevated pressure by a valve needle fitted to the valve body of the injection valve, from the injection valve fuel chamber to the engine cylinder where the fuel is further supplied from the fuel chamber at a pressurized vent. a pressure measuring chamber, which is equipped with pressure measuring means to monitor the operation of the injection valve.

The arrangement according to the invention can be used to observe the time of the start of the spray, the time of the stop. In particular, the arrangement according to the invention is suitable for: a spray arrangement utilizing a common-stock depot, whereby the · ·. ·· *. to monitor for possible fuel leaks from the common rail to the t · • injection valve.

• · · * «· • ·« »· 3 113684

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: - Figure 1 schematically shows a needle valve assembly according to the invention, and - Figure 2 schematically shows a detail of the 5 needle valve assembly according to the invention.

In the figure, reference numeral 1 shows a valve body having a needle valve assembly 2. The valve body is two-piece and the lower part adjacent to the cylinder 11 of the engine comprises a fuel chamber 5 from which fuel is injected into the cylinder 11. The valve needle 5 'of the needle valve assembly. The fuel chamber 5, in turn, is connected via a conduit 3 to a fuel source 4, which is preferably a common pressure storage. The valve needle, based on its position, controls the injection of fuel from the fuel chamber 5 into the cylinder 11 of the engine. The valve needle assembly may be a known solution that operates in a manner known per se, so its construction, function, or control is not shown.

According to the invention, the valve body 1 is provided with a pressure measuring chamber 6 fitted with a pressure measuring device 7. The pressure measuring device measures the pressure in the pressure measuring chamber 6 and transmits the measurement information. for further processing into the engine control system (not shown).

The pressure measuring chamber 6 communicates with the fuel chamber 5 via an annular groove 5 "and a channel 5 '. The annular groove 5" may be uniform: i.e. open throughout the entire circumference of the valve body, the pressure measuring chamber 6; and channel 5 through groove 5 ". The annular groove 5 "can also be arranged s a 25 to extend only a portion of the distance about the longitudinal axis of the valve body, wherein the pressure measuring chamber 6 communicates with the channel 3 through the fuel chamber 5.

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An annular groove is arranged between the upper and lower parts of the valve body. In addition, the pressure measuring chamber 6 is connected to a fuel return duct 8 through which the fuel to be returned from the valve may flow out, for example back to the fuel tank (not shown). To valve body 1, fuel chamber 5 and. between the pressure measuring chamber 6, the first pressure reducing means 9 are arranged, which causes the pressure in the pressure measuring chamber 6 to be substantially lower than that of the fuel chamber 5. Accordingly, after the pressure measuring chamber 6, the second pressure reducing elements 9 'are arranged. By appropriately selecting the first 9 and second pressure relief members 9 ', i.e. by appropriately dimensioning their flow resistances, the pressure level in the pressure measuring chamber 6 can be set to such a level that the pressure measurement conditions become appropriate.

The pressure relief members 9, 9 'may be, for example, a suitably sized bore, nozzle, flange, or the like, which causes a pressure drop in the fuel flow. Suitable throttles may be experimentally determined for each nozzle and / or engine type, i.e., individually. Preferably, the first pressure relief means 9 comprises a nozzle / flange member that is interchangeable to suit the particular application. Preferably, the second pressure relief members 9 'comprise a flow port opening of a suitable size. Taken together, these provide an overall advantageous solution.

Preferably, check valves 10,10 'are also fitted to the valve body. The first non-return valve 10 is disposed between the first pressure relief means 9 and the pressure measuring chamber 6. The first non-return valve 10 prevents the fuel from returning to the fuel chamber 5. The second non-return valve 20 'is disposed after the pressure measuring chamber 6, preferably after the second pressure relief means 9'. The second non-return valve 10 'also enables: · monitoring of fuel leaks, since no fuel can flow from the return duct 8 to the pressure measuring chamber 6.

In some cases, the operation of the system of the invention may be improved by the piston member 21 shown in Fig. 2. This piston member is arranged to comprise a first portion 22 adapted to accommodate the first within the pressure relief means 9, and a second portion 23 having a greater cross-sectional dimension than the first portion 22. The piston member is thus at different points along its longitudinal axis: 30 of different diameter. The piston member 21 is adapted to move under the influence of fuel flow and pressure fluctuations between positions where the first portion 22 is located within the pressure relief means 9 and the first portion 22 * · 'is outside the pressure relief means 9. Thus, the piston member 21 is adapted to act as a non-return valve. The piston member may serve as a replacement for the non-return valve 10 and may also assist in lowering the fuel pressure.

5, 113684

The method according to the invention operates so that when the needle valve assembly 5 is connected to the fuel source 4, preferably the common rail pressure reservoir through the channel 3, the pressure in the fuel chamber 5 rises to the injection pressure. As a result, fuel flows through duct 5 'to annular groove 5 "through the first pressure relief means 9 and back vent 10 to the pressure measurement chamber 6. From the pressure measurement chamber, a small amount of fuel can flow through the second pressure relief members 9' and backflow valve 8 The arrangement causes the pressure in the pressure measuring chamber 6 to be such that it is possible to monitor the pressure with sufficient accuracy. By monitoring the pressure below the injection pressure, the status of the valve unit and its operation can provide better control over engine combustion and thus better operation and performance.

The arrangement allows accurate measurement of pressure variations from the pressure measuring chamber 6, which is substantially lower than the fuel 20 in chamber 5. The fuel injection valve according to the invention is dimensioned to: preferably so that the pressure in the pressure measuring chamber 6 rises typically below 50 bar; to the bar level, where the injection pressure in the fuel chamber 5 can typically be in the order of 1000 to 1500 bar.

The pressure measuring unit 7 may in some cases also be a separate device functionally connected only to the valve body '·· *'. The invention may be applied in systems where the fuel pressure of the injection valve is maintained between injections, or in which the pressure is not maintained between injections.

It is thus clear that the above technical solutions are exemplary only, so that the invention is not limited to the embodiment shown, but many variations are conceivable within the scope of the appended claims.

Claims (9)

A fuel injection valve, comprising a needle valve assembly (2) mounted on a valve body (1) having a valve needle (2 ') for directing fuel injection into an engine cylinder (11) from a fuel chamber (5) fitted to a valve body (1) and , adapted for cooperating with the fuel chamber (5) and pressure measuring means (7) adapted for cooperating with the pressure measuring chamber (5), characterized in that the pressure measuring chamber (6) is arranged to cooperate with the fuel pressure chamber (5). 2. Insprutningsventil enligt patentkrav 1, kännetecknad av att tryckmätnings chamber (6) förenad med en returledning (8) för bränsle för att bortleda avlägsnande bränsle bort fran insprutningsventilen. Injection valve according to Claim 1, characterized in that the pressure measuring chamber (6) is connected to a fuel return duct (8) in order to drain the outgoing fuel from the injection valve. Insprutningsventil enligt patent krav 1, a rotating deck (5) and a första decompressionsorganen (9), and a standard 15 en bakslagsventil (10). Injection valve according to claim 1, characterized in that a non-return valve (10) or the like is arranged between the pressure measuring chamber (5) and the first pressure relief means (9). Insprutningsventil enligt patent krav 1 eller 2, a rotary traction device (6) and returledningen (8) and anordnade andra decompression organ (9 '). Injection valve according to Claim 1 or 2, characterized in that the pressure measuring chamber (6) and the return duct (8) are fitted with others,. pressure relief means (9 '). Injection valve according to claim 4, characterized in that a second: non-return valve (10 ') or the like is fitted between the second pressure relief means (9') and the fuel return duct. 5. Insprutningsventil enligt patentkrav 4, kännetecknad av att mellan de andra: · 20 decompressionsmedlen (9 ') and returledningen för bränsle anordnad en an-, nan bakslagsventil (10') eller motsvarande. 6. Insprutningsventil enlig patent krav 1 eller 4, kännetecknad av att decompressionsmedlen (9,9 ') omfattar en borrning, to munstycke, en fläns eller mot- • · * ··· * weighted av warmplig storlek. . ·. 25 7. Förfarande vid bränsleinsprutning, vid vilket bränsle leds i förhöjt tryck con trollerad av ventilnälen (2 ') arrangerad i venthuset (1) frän bränslekammaren. · F (5) account cylindern (11) av en motor, kännetecknat av att bränle leds frän • · · '· bränslekammaren (5) i förhöjt tryck genom decompressionsverktyg (9) arran- ·· * gerade i venthuset account tryckmätningskammaren (6), vid vilken tryckmätnings-, · 30 verktygen (7) är anordnade attontrollera insprut. . β 113684 Injection valve according to claim 1 or 4, characterized in that the '··· * pressure relief means (9,9') comprises a suitable bore, nozzle, flange or the like. «• · · * 6, 113684 7. Method of Fuel Injection, in which the fuel is introduced into the • · ·. *. at a pressurized pressure controlled by a valve needle (2 ') fitted to the injection valve valve body (1) from the injection valve fuel chamber (5) to the engine • ·' ··· 'cylinder (11), characterized in that fuel is supplied from the fuel chamber (5). ) at elevated pressure through pressure relief means (9) provided on the valve body (6) to a pressure measuring chamber (6), whereby the operation of the injection valve is monitored by the pressure measuring means (7). 8. Förfarande enligt patentkrav 7, kännetecknat av att bränslets tryck sänks account minst en tiondedel av bränslekammarens (5) tryck da bränsle leds account tryckmätningskammaren (5) genomic decompression tree (9). A method according to claim 7, characterized in that the fuel pressure is lowered to at least one tenth of the pressure of the fuel chamber (5) by passing it through the pressure relief means (9) to the pressure measuring chamber (5). Method according to Claim 7, characterized in that the fuel is led from the pressure measuring chamber (6) to the fuel return channel (8). * φ I »» I · • • • • • • • I * 1 · t · * 1 1 • »· • ♦ • • • • 1 · • 8 113684 Insprutningsventil for bränsle, letting omfattar en ventnord anordnad starvillenhet (2), account leasing & vent (2 ') att styra brnslein-sprutning account en Motors cylinder (11) fran en i venthuset arrangerat bränsle-5 kammare (5) ), samt en tryckmätningskammare (6) för bränsle, I am looking at the brewing chamber (5), och tryckmätningsmedel (7), and the braking chamber (5), the bracket (6) The genome of bränslekammaren (5) första decompressionsorgan (9). 9. Förfarande enligt patentkrav 7, kännetecknat av att bränsle tillförs fran 5 tryckmätningskammaren (6) account returledningen (8) för bränsle. «I · • · · *« I • • t • · • · * * * ♦ · • 1 »• 1 • ·» • «•» · • · »·