Patent ID: 9664167
Date: 2017-05-30
CPC Classifications: F02D,F02M,F16K,Y10T

Claim:
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.