Title of Invention

FLOW LIMITING VALVE OF FUEL SYSTEM

Abstract A fuel system shut-off valve including a body part in which there is arranged a fuel space having an inlet connection and an outlet connection, actuating means comprising a main actuator arranged in the fuel space for movement between a first limit position and a second limit position, and a force arrangement causing a force to act on the main actuator opposite in direction to the fuel main flow direction and urging the main actuator towards the first limit position, the actuating means further comprising an auxiliary actuator movable relative to the main actuator characterised in that the auxiliary actuator is movable relative to the main actuator for preventing fuel flow from the inlet connection to the outlet connection when the main actuator is in the second limit position.
Full Text FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
as amended by
THE PATENTS (AMENDMENT) RULES, 2006
COMPLETE SPECIFICATION
[See Section 10; rule 13]
"A FUEL SYSTEM SHUT-OFF VALVE"
WARTSILA TECHNOLOGY OY AB, of John Stenbergin ranta 2, FIN-00530 Helsinki, Finland,
The following specification particularly describes the invention and the manner in which it is to be performed:




The present invention relates to a fuel system shut-off valve according to the preamble of claim 1.
Presently, a so-called common rail storage injection system is generally used in connection with internal combustion engines. In such a system, fuel under injection pressure is injected to the combustion chamber of the engine by controlling the injection valve. If the injection valve is defective, this enables the situation in which fuel may leak uncontrollably into the combustion chamber of the cylinder. To prevent this, the publications US 3 780 716 and WO 95/17594 propose a shut-off valve for limiting the fuel flow volume. In the shut-off valve there is a cylinder space which further includes a piston means provided with a spring load acting against the fuel flow direction in an injection situation. In normal operation the fuel amount needed for each injection corresponds to the volume displaced by the piston movement. If for some reason the shut-off valve continues to leak, the piston moves to its other extreme position in which it shuts the flow off.
In publication GB 2317922 there has also been represented another shut-off valve limiting the flow volume. In the initial situation, the pressure acts upon a smaller surface area on the fuel admission side in which case, at a specific pressure, the force is naturally smaller being in proportion to the surface area acted upon. However, the problem of this solution is the absolute tightness requirement and consequently it is very sensitive in regard to the fuel quality. If the sealing surface of this smaller surface area leaks, the solution doesn't work and the pressure is applied to the totality of the surface area and the piston may move to its second extreme position closing the flow. Especially in large power

plant and marine engines the fuel can be such that the presented solution does not function reliably enough.
Also, the prior art flow shut-off valves have generally problems related as well to situations in which the fuel viscosity is low, for example when heavy fuel oil is used and/or when the fuel temperature is before starting lower than the normal operating temperature. Consequently, the equalization of the fuel pressure over the piston means does not occur rapidly enough and the piston may move to its other extreme position and closes the injection connection.
An object of the present invention is therefore to provide a fuel system shut-off valve by which the prior art disadvantages are avoided. An objective of the present invention is especially to provide a shut-off valve by which the unintentional closure on starting phase can be avoided.
Objects of the invention can be achieved mainly in a way that is represented in more detail in claim 1 and in other dependent claims.
The fuel system shut-off valve according to the invention includes a body part, in which there is arranged a fuel space having an inlet and an outlet connection, an actuator movably arranged in the fuel space, according to the position of which fuel may either flow through the shut-off valve or the fuel flow is prevented, and a force arrangement causing a force opposite to the fuel main flow direction upon the actuator. The actuator includes an auxiliary actuator movably aranged thereto.
Both the actuator and the auxiliary actuator include, on the fuel space inlet connection side, a first surface area and a second surface area, respectively, bordering the space in question and the second surface area formed by the auxiliary actuator is smaller than the first surface area formed by the actuator. The auxiliary actuator is arranged to be movable for providing the closing and

opening of the flow connection between the inlet and outlet connection. For this purpose the auxiliary actuator is provided with a sealing surface.
The force arrangement arranged in the actuator for bringing about a force opposite direction to the fuel main flow direction produces force also to the auxiliary actuator and this has an effect on the determination of the reciprocal position of the actuator and the auxiliary actuator, in other words, they advantageously share a common force arrangement.
The fuel space of the shut-off valve is preferably cylindrical and the actuator includes a piston means, the diameter of which corresponds substantially to the fuel space diameter, in which there is fitted a hole in the direction of its longitudinal axis, and the auxiliary actuator is movably arranged into the hole of the piston means.
The counter surface of the auxiliary actuator sealing surface may be arranged in connection with the outlet connection or in connection with the actuator as well depending on the way the shut-off valve is implemented.
Several advantages are obtained with the invention. Firstly, the operation of the solution is reliable on starting of the engine. The operation pressure of the shut-off valve auxiliary actuator can easily be dimensioned as desired and, mainly, the operation of the shut-off valve depends on the pressure solely. Further, the fuel qualities have only a slight effect on the operation and the amount of possible dirt particles in the fuel does not affect the starting operation.
The invention is explained below by way of example only, with reference to the accompanying schematic drawings, in which:
- Figure 1 shows how the shut-off valve according to the invention is applied to a fuel injection system,
- Figure 2 shows an embodiment of the shut-off valve according to the invention in its basic position,

- Figure 3 shows the shut-off valve according to Figure 2 during the injection,
- Figure 4 shows the shut-off valve according to Figure 2 in its second extreme position,
- Figure 5 shows the closed shut-off valve according to the Figure 2, and
- Figure 6 shows another shut-off valve according to the invention.
As shown very schematically in Figure 1, the shut-off valve according to the invention 4 can be adapted to a common rail fuel storage injection system. The common rail storage injection system is known as such and it is not explained here in more detail. The common rail storage injection system includes as its principal components a common rail storage 1, in which there is fuel under high pressure to be injected to the engine and with which the injection valve 2 is in flow connection. From the common rail storage 1 there is arranged a fuel channel ductwork 3, 3' for the injection valve 2 dosing fuel to each cylinder (not represented). In the common rail storage there is maintained during the operation a pressure by which an adequate injection pressure is provided to the injection valve 2. Each injection valve 2 comprises control means (not represented) for controlling the injection independently. In the fuel channel ductwork 3, 3' there is arranged a shut-off valve 4, the operation of which is explained in the following by referring to Figures 2-5.
The shut-off valve is represented in its initial state in Figure 2. The shut-off valve includes a body part 5, in which a cylindrical fuel space 6 is arranged. In connection with the fuel space there is adapted an inlet connection 7 and an outlet connection 8 for the fuel. In the fuel space 6 of the body part 5 there is fitted an actuatoir'9, which advantageously comprises a piston arrangement or alike. On grounds of the position of the piston arrangement 9 fuel may either flow via the shut-off valve or the fuel flow may be prevented. The shut-off valve 4 further comprises a spring 10, under the influence of which the piston arrangement 9 is in the situation shown in Figure 1 against a shoulder 5' of the

body part 5. In normal running conditions between the injections, the shut-off valve 4 is in the position of Figure 2.
When during the normal operation the injection valve 2 starts the injection, a pressure difference develops over the shut-off valve 3, in other words between the inlet connection 7 and the outlet connection 8, in which case the piston arrangement 9 sets off and moves until the injection stops and the pressure difference equalizes. This situation is described in Figure 3. In this situation the amount of the fuel to be injected is equivalent to the volume displaced by the movement of the piston arrangement 9 in the fuel space 6.
An auxiliary actuator i.e. an auxiliary piston 12 is movably arranged in connection with the piston arrangement 9. The piston arrangement 9 includes in the section on the inlet connection 7 side of the fuel space 6 an area 9' limiting the space 6 in question, whereupon the fuel space pressure acts and in normal operation the auxiliary piston 12 moves with the piston arrangement 9 without reciprocal movement of these two.
In case that the shut-off valve 2 leaks or it doesn't close up for some reason after the injection, the common rail storage 1 pressure pushes the piston arrangement 9 together with the auxiliary piston 12 to its other extreme position represented in Figure 4. In this position of the piston arrangement 9 the flow into the injection valve 2 is strongly restricted, because the totality of the flow goes via a throttle 11. This throttle connects the sections on different sides of the fuel space 6 piston arrangement with each other. The pressure difference over the piston arrangement 9 increases and when it reaches a specific limit, the auxiliary piston 12 moves in regard to the piston arrangement 9 and the sealing surfaces 13, 13' close up and shut the flow off, which situation is shown in Figure 5. Here the counter surface 13' of the auxiliary piston 12 sealing surface 13 is arranged in connection with the outlet connection 8. This operation is brought about so that the auxiliary piston 12 includes an area 12' bordering a space in the section on the fuel compartment 6 inlet connection 7 side and this

area is smaller than the corresponding area 9' of the piston arrangement 9, in which case primarily a common movement of the piston arrangement 9 and the auxiliary piston 12 takes place and only when the pressure difference has exceeded a certain limit does the auxiliary piston 12 move in the piston arrangement. Consequently, the pressure moving the auxiliary piston 12 is directed only at the area determined by its diameter and the movement requires a greater pressure than the pressure enabling the movement of the whole piston arrangement 9.
The shut-off valve 4 according to the invention operates on starting of the engine for example in heavy fuel applications as follows. When the fuel circulation is launched before the engine is started up, the pressure of the low-pressure side of the fuel system effects the inlet connection 7. In this initial situation the outlet connection 8 side can be almost free of pressure or even full of air. In the next phase the piston arrangement 9 of the shut-off valve 4 moves into the position illustrated in Figure 4, in other words into its second extreme position. It may be presumed, for example, that the pressure on the low-pressure side of the fuel system is around 7 bar. The shut-off valve 4 can be dimensioned for example so that the pressure difference needed for moving the auxiliary piston 12 to the position in Figure 5 is 25 bar. This means, in practice, that the shut-off valve 4 stays open and makes possible the filling of the section on the outlet connection 8 side and the section subsequent thereto from the injection system and the equalization of the pressure between the inlet connection 7 and the outlet connection 8. When the pressure between the inlet connection and the outlet connection has sufficiently equalized, the piston arrangement 9 of the shut-off valve moves to the position illustrated in Figure 2 and the engine can be started without problems. This way the throttle 11 can be dimensioned only according to the desired return speed of the piston arrangement 9 (in normal situation when the engine is running). If there is for example a pipe breakage on the outlet connection 8 side of the shut-off valve when the engine is operating, the shut-off valve closes up immediately.

Another shut-off valve embodiment is represented in Figure 6. This embodiment corresponds otherwise to the one represented in Figures 2-5, but the auxiliary piston 12 has been arranged differently to function with the piston arrangement 9 itself as flow closing means. In this embodiment there is a bolt or alike 12 matched into the piston arrangement hole so that the channel 11 going therethrough opens from the other end thereof in relation to the piston arrangement of the fuel space 6 to the section on the outlet connection 8 side, and from the other end thereof to the piston arrangement of the fuel space 6 to section on the inlet connection 7 side. Now, if the pressure difference over the piston arrangement 9 exceeds a specific limit, the bolt 12 moves towards the outlet connection, in which case the sealing surfaces 13, 13' end up against each other. Here the movement in question is just about to take place. In an embodiment according to Figure 6 the counter surface 13' of the auxiliary piston sealing surface 13 is arranged in connection with the piston arrangement 9.
The invention is not limited to the embodiments shown, but several modifications of the invention are reasonable within the scope of the attached claims.

We Claim:
1. A fuel system shut-off valve (4) including a body part (5) in which there is arranged a fuel space (6) having an inlet (7) connection and an outlet (8) connection, actuating means comprising a main actuator (9) arranged in the fuel space for movement between a first limit position and a second limit position, and a force arrangement (10) causing a force to act on the main actuator (9) opposite in direction to the fuel main flow direction and urging the main actuator towards the first limit position, the actuating means further comprising an auxiliary actuator (12) movable relative to the main actuator (9) characterised in that the auxiliary actuator (12) is movable relative to the main actuator (9) for preventing fuel flow from the inlet (7) connection to the outlet (8) connection when the main actuator is in the second limit position.
2. The shut-off valve (4) as claimed in claim 1, wherein both the actuator (9) and the auxiliary actuator (12) include in the section on the inlet connection (7) side of the fuel space a first area (9') bordering the space in question and a second area (12'), respectively, and that the second area (12') formed by the auxiliary actuator (12) is smaller than the first area (9') formed by the actuator.
3. The shut-off valve (4) as claimed in claim 1 or 2, wherein the auxiliary actuator (12) is movably arranged for providing the closing and opening of the flow connection between the inlet connection (7) and the outlet connection (8).
4. The shut-off (4) as claimed in claim 3, wherein the auxiliary actuator (12) is provided with a sealing surface (13) for closing the flow connection between the inlet connection (7) and the outlet connection (8).

5. The shut-off valve (4) as claimed in any one of the preceding claims, wherein the force arrangement (10) arranged in the actuator for bringing about a force in opposite direction to the fuel main flow direction, produces force to the auxiliary actuator (12), which has an effect on the determination of the reciprocal position of the actuator (9) and the auxiliary actuator (12).
6. The shut-off valve (4) as claimed in any of the preceding claims, wherein the fuel space (6) is cylindrical and that the actuator (9) includes a piston means, the diameter of which substantially corresponds to the fuel space diameter, in which there is fitted a hole parallel with its longitudinal axis, and that the auxiliary actuator (12) is movably arranged into the hole of the piston arrangement (9).
7. The shut-off valve (4) as claimed in claim 4, wherein a counter surface (13') of the auxiliary actuator sealing surface is arranged in the outlet connection (8).
8. The shut-off valve (4) as claimed in claim 4, wherein a counter surface (13') of the auxiliary actuator (12) sealing surface is arranged in connection with the main actuator (9).
9. The fuel system shut-off valve substantially as hereinbefore described with reference to the accompanying drawings.
Dated this the 3^^ day of May, 2002


Documents:

400-mum-2002-abstract(10-04-2007).doc

400-mum-2002-abstract(10-04-2007).pdf

400-mum-2002-cancelled pages(10-04-2007).pdf

400-mum-2002-claims(granted)-(10-04-2007).doc

400-mum-2002-claims(granted)-(10-04-2007).pdf

400-mum-2002-correspondence(19-04-2007).pdf

400-mum-2002-correspondence(ipo)-(26-12-2006).pdf

400-mum-2002-drawing(10-04-2007).pdf

400-mum-2002-form 1(03-05-2002).pdf

400-mum-2002-form 1(10-04-2007).pdf

400-mum-2002-form 18(13-04-2006).pdf

400-mum-2002-form 2(granted)-(10-04-2007).doc

400-mum-2002-form 2(granted)-(10-04-2007).pdf

400-mum-2002-form 3(03-05-2002).pdf

400-mum-2002-form 3(05-09-2002).pdf

400-mum-2002-form 3(10-04-2007).pdf

400-mum-2002-form 5(03-05-2002).pdf

400-mum-2002-petition under rule 137(10-04-2007).pdf

400-mum-2002-petition under rule 138(10-04-2007).pdf

400-mum-2002-power of authority(10-04-2007).pdf

400-mum-2002-power of authority(24-07-2002).pdf

abstract1.jpg


Patent Number 213201
Indian Patent Application Number 400/MUM/2002
PG Journal Number 04/2008
Publication Date 25-Jan-2008
Grant Date 24-Dec-2007
Date of Filing 03-May-2002
Name of Patentee See attached documents
Applicant Address See attached documents
Inventors:
# Inventor's Name Inventor's Address
1 See attached documents See attached documents
PCT International Classification Number F61K 15/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA