GB2243432A

GB2243432A - A fuel line arrangement

Info

Publication number: GB2243432A
Application number: GB9009424A
Authority: GB
Inventors: John Mcglynn
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1990-04-26
Filing date: 1990-04-26
Publication date: 1991-10-30
Anticipated expiration: 2010-04-26
Also published as: GB2243432B; GB9009424D0

Abstract

A fuel rail 16 has fuel entry and exit passages. A fuel line connector (24) is connected between one or other of the passages and a fuel line and the connector itself includes a pressure sampling valve (50) to which a pressure measuring device can be connected to measure the fuel pressure in the rail. <IMAGE>

Description

A FUEL LINE ARRANGEMENT This invention relates to a fuel line arrangement for use in a motor vehicle fuel system to allow sampling of the pressure in the fuel system.

In fuel injected engines, the fuel is pumped from the fuel tank to a fuel rail which acts as a manifold from which the fuel injectors are supplied with fuel. There are both fuel supply and fuel return lines connected to the fuel rail and when the engine is running, there is a continuous flow of fuel in both the supply and return lines.

As part of an engine diagnostic process, it is necessary to measure the fuel pressure in the fuel system. This has conventionally been done by mounting a sampling valve in the fuel rail in such a way that a pressure measurement device can be connected up to the sampling valve to measure the pressure. However the inclusion of such a pressure sampling valve in the fuel rail itself has required the drilling of an additional hole through the wall of the rail and the fitting in this hole of a valve body. This gives rise to the possibility of fuel leaks around the valve body. It is of the utmost importance that complete fuel integrity be maintained in the region of the fuel rail, and that any possibility of fuel leakage be rigorously excluded.Furthermore the drilling of a hole in the fuel rail at this point may result in metal fragments or swarf falling into the internal passages of the rail. Such fragments may lead to a blockage of some of the various passages between the fuel rail, the injectors and the engine cylinders.

According to a first aspect of the present invention, there is provided a fuel line arrangement comprising a fuel rail, a fuel passage through the rail, a fuel inlet to and a fuel outlet from the rail, and a fuel line connector connected between either the inlet or the outlet and a fuel line, the connector including a pressure sampling valve.

According to a second aspect of the invention, there is provided a fuel line connector for providing a connection between fuel line components, wherein the connector has an inlet and an outlet and a fuel pressure sampling valve mounted between the inlet and the outlet for sampling pressure in the fuel line, the valve comprising a moveable valve member which closes against a seat in a valve housing which is formed integrally with the inlet and the outlet.

Preferably either the inlet or the outlet is provided with a spigot on which a hose can be secured. The other of the inlet and outlet can be adapted to connect to a threaded boss on another fuel line component.

The connector preferably has a one-piece body which incorporates the inlet, the outlet and the valve housing.

The valve housing may include an external threaded portion onto which a pressure measuring device can be connected in such a way that screwing on the pressure measuring device to the external thread also results in opening of the valve. The valve member is preferably spring loaded into its closed position.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a four cylinder internal combustion engine with a fuel rail connected to the engine; Figure 2 is a section through a fuel line connector in accordance with the invention, shown in conjunction with part of a fuel rail; Figure 3 is a second view of the connector shown in Figure 2 with a fuel pressure sampling valve in place; and Figure 4 shows a pressure sampling valve in more detail.

Figure 1 shows an engine block 10 with an inlet manifold 12 and an exhaust manifold 14. On the inlet manifold side of the engine, a fuel rail 16 is mounted. A fuel inlet pipe 18 introduces fuel to the rail 16, and an outlet pipe 20 returns fuel to the fuel tank. From the rail 16, fuel is supplied to fuel injectors 22, one for each cylinder.

The fuel inlet pipe 18 is connected to the fuel rail 16 by means of a fuel line connector 24, and this connector will be described in more detail with reference to Figures 2, 3 and 4.

The connector 24 has an inlet 26 and an outlet 28. It is however to be understood that the connector can operate with the flow in either direction, and thus the port 26 could be the outlet and the port 28 could be the inlet.

However for the purposes of this description, reference will continue to be made to the inlet 26 and the outlet 28, and this assumes that flow through the connector is in the direction indicated by the arrow 30. The main flow passage through the connector follows a L-shape, with a branch passage 32 leading off from the corner of the L-shape. At the top of this branch passage there is a valve housing 34 which includes an annular seating region 36 and an internal threaded region 38. On the exterior of this branch passage is an external thread 40.

The outlet end 28 is designed to fit within an externally threaded spigot 42 on the fuel rail 16, and as can be seen in Figure 3, a nut 44 fits over a shoulder 46 on the connector and pulls the connector tightly down into the spigot 42. Suitable seals (not shown in the Figures) will be included to ensure that a fluid tight seal is obtained (in a known manner) between the connector and the fuel rail.

Although Figures 2 and 3 show one particular spatial arrangement of the inlet 26, outlet 28 and branch passage 32, it is to be understood that this is only an example and that these three features can be arranged in a different spatial arrangement so long as there is a flow passage from the inlet to the outlet, and so long as the branch passage communicates with this flow passage. The precise arrangement in a particular case will be chosen in accordance with packaging and accessability requirements.

Figure 3 shows the exterior of the connector 24, with barbed rings 48 formed on the inlet 26 to retain a flexible hose pushed onto the inlet. In the branch passage 32, a valve 50 is mounted, and this valve will be described in more detail with reference to Figure 4, in which the valve is shown on a much enlarged scale.

The valve has an upper externally threaded portion 52 which screws into the internal thread 38 in the branch passage 32. As this is threaded in, an elastomeric seal ring 54 makes sealing contact with the tapered annular seat 36 in the branch passage to provide an effective closure of the passage. At the bottom end of the valve there is a valve member in the form of a cup washer 56 with an internal elastomeric annular seal which seats against an annular rim 58 on the valve body.

The cup 56 is mounted on a rod 60 which extends right through the valve from a head 62 at the top down to the cup 56 at the bottom. An internal spring (not shown) normally biases the rod 60 in an upward direction so that the seal in the cup 56 seats against the annular rim 58 to close the valve.

To open the valve, it is necessary to press the plunger pin 60 downwards so that the cup 56 is moved against the influence of the internal spring from the position shown in bold lines to the position 56a shown in dotted lines, and in this condition the valve is open.

The valve will normally be opened by screwing an end of a pressure measuring device onto the external threads 40 of the branch passage. The end of the pressure measuring device will then be constructed so that as it is tightened onto the threads 40, a part of the pressure measuring device depresses the head 62 of the plunger and opens the valve thus communicating the fuel passage 26,28 with the interior of the pressure measuring device. However as soon as the pressuring measuring device is removed, the internal spring will lift the plunger 60 and close the valve again.

A protective cap may be screwed onto the threads 40 to protect the valve between the times when a pressure measuring reading is being taken.

The mounting of the pressure sampling valve in a component which is separate from the fuel rail itself means that there is less danger of foreign matter being introduced into the interior of the fuel rail during fitting of the valve, and allows the fluid tightness of the valve 50 in the connector 24 to be tested and confirmed well away from the final assembly line. There will then only be the one joint, that formed by the nut 44 and spigot 42, which needs to be considered in the final assembly.

The connector body 24 can be made by any suitable manufacturing technique. It is however preferred that the body be made in one piece as shown in Figure 2 to minimise any possibility of leaks and to reduce assembly operations.

The connector can be made by casting or forging followed by machining.

Claims

1. A fuel line arrangement comprising a fuel rail, a fuel passage through the rail, a fuel inlet to and a fuel outlet from the rail, and a fuel line connector connected between either the inlet or the outlet and a fuel line, the connector including a pressure sampling valve.

2. A fuel line connector for providing a connection between fuel line components, wherein the connector has an inlet and an outlet and a fuel pressure sampling valve mounted between the inlet and the outlet for sampling pressure in the fuel line, the valve comprising a moveable valve member which closes against a seat in a valve housing which is formed integrally with the inlet and the outlet.

3. A fuel line connector as claimed in Claim 2, wherein either the inlet or the outlet is provided with a spigot on which a hose can be secured.

4. A fuel line connector as claimed in Claim 3, wherein the other of the inlet and outlet is adapted to connect to a threaded boss on another fuel line component.

5. A fuel line connector as claimed in any one of Claims 2 to 5, which has a one-piece body incorporating the inlet, the outlet and the valve housing.

6. A fuel line connector as claimed in any one of Claims 2 to 5, wherein the valve housing includes an external threaded portion onto which a pressure measuring device can be connected in such a way that screwing on the pressure measuring device to the external thread also results in opening of the valve.

7. A fuel line connector as claimed in Claim 6, wherein the valve member is spring loaded into its closed position.

8. A fuel line connector substantially as herein described with reference to Figures 2 to 5 of the accompanying drawings.

9. A fuel line arrangement substantially as herein described with reference to Figure 1 of the accompanying drawings.