Granted Patent B2

US 9,664,167 · App. 14/435,508 · Granted May 30, 2017

Abstract

Claims (28)

1. A valve arrangement for use in limiting the pressure of fuel within an accumulator volume of an accumulator fuel system to a predetermined threshold level, the valve arrangement comprising:

a valve outlet for communication with a low pressure drain;

a valve housing provided with a valve housing bore for receiving fuel from the accumulator volume;

a valve member comprising a ball slidably received in a first section of the housing bore, said member having a closed position in which it is engaged with a valve seating defined by the valve housing bore to prevent fuel flow from the accumulator volume to the valve outlet;

biasing means for urging the valve member towards the valve seating;

a first restricted flow means for restricting the flow of fuel between the accumulator volume and the valve outlet during a first stage of valve opening movement as soon as the valve member is lifted from the valve seating;

a second restricted flow means effective during a second stage of valve opening movement which follows the first stage to provide a greater restriction than during the first stage; and

a third restricted flow means effective during a third stage of valve opening movement which follows the second stage to provide a variable restriction to fuel flow dependent on the extent of opening movement of the valve member;

wherein each of the first, second and third restricted flow means is defined between the ball and the first section of the valve housing bore;

wherein the valve seating is located on a first conical section which is defined by the valve housing bore;

wherein the first restricted flow means is defined between the valve member and the valve seating;

wherein the third restricted flow means is defined by a second conical section, which is defined by the valve housing bore;

wherein the first and second conical sections define an intermediate section therebetween, wherein the intermediate section cooperates with the valve member to define the second restricted flow means; and

wherein the intermediate section is arranged to have a taper, such that the level of restriction is increased as the valve member moves away from the first conical section towards the second conical section.

2. A valve arrangement for use in limiting the pressure of fuel within an accumulator volume of an accumulator fuel system to a predetermined threshold level, the valve arrangement comprising:

a valve outlet for communication with a low pressure drain;

a valve housing provided with a valve housing bore for receiving fuel from the accumulator volume;

a valve member comprising a ball slidably received in a first section of the housing bore, said member having a closed position in which it is engaged with a valve seating defined by the valve housing bore to prevent fuel flow from the accumulator volume to the valve outlet;

biasing means for urging the valve member towards the valve seating;

a first restricted flow means for restricting the flow of fuel between the accumulator volume and the valve outlet during a first stage of valve opening movement as soon as the valve member is lifted from the valve seating;

a second restricted flow means effective during a second stage of valve opening movement which follows the first stage to provide a greater restriction than during the first stage;

a third restricted flow means effective during a third stage of valve opening movement which follows the second stage to provide a variable restriction to fuel flow dependent on the extent of opening movement of the valve member; and

a piston member which is situated between the biasing means and the valve member;

wherein each of the first, second and third restricted flow means is defined between the ball and the first section of the valve housing bore.

3. A valve arrangement according to claim 2 , wherein the valve member and the piston member is formed together as an integrated component.

4. A valve arrangement according to claim 2 , further comprising means to limit the range of movement of the piston member.

5. A valve arrangement according to claim 2 , wherein the piston member is provided with an extension which cooperates with the valve member to aid positioning and/or retention of the valve member.

6. A valve arrangement according to claim 5 , wherein an end face of the extension is concave to aid positioning and/or retention of the valve member.

Assignments (6)