Metering valve for pilot fuel injection

A metering valve for a pilot injection system, said metering valve comprising:

• a valve housing having fuel inlet and outlet means and a bore communicating with said means;
• a spool type valving member slideably moveable in said bore in stepped fashion along a path extending from a first position blocking communication between said means to a second position;
• passage means in said spool operative during movement of said valving member along said path to define a first continuous passage through said valve housing and then a second continuous passage through said valve housing, said first and second continuous passages defined by serially connecting said inlet means, said passage means, and said outlet means;
• cam means having a lobe smoothly increasing on one side and abruptly decreasing in two steps on the other side;
• means biasing said spool toward said lobe;
• drive means for effecting relative movement between said cam means and said spool, the smooth side of said lobe operative to slide said spool to said first position in response to said relative movement and the steps allowing sliding movement of said spool in stepped fashion along said path by said biasing means in response to continuing relative movement.

An improved metering valve in a pilot injection system of the type including a source of pressurized fuel, a nozzle for delivering the fuel to a cylinder of an internal combustion engine, means for communicating the source with the nozzle, and periodic means for blocking and unblocking the communicating means in a timed relation to the position of the piston in the cylinder, said metering valve comprising:

• a valve housing having
• a bore,
• fuel inlet means communicating at one end with said bore and connected at the other end to said source by said communicating means, and
• fuel outlet means communicating at one end with said bore and connected at the other end to said nozzle by said communicating means;
• a spool type valving member slideably moveable in said bore in two stepped fashion along a path extending from a first position blocking communication between said inlet and outlet means to a second position;
• passage means in said spool operative during movement of said valving member along said path to meter a pilot fuel charge to said outlet means during the first step of such movement and then a main fuel charge to said outlet means during the second step of such movement;
• cam means having a lobe smoothly increasing on one side and abruptly decreasing in two steps on the other side;
• means biasing said spool toward said lobe;
• and
• means driven at a velocity proportional to engine speed and effecting relative movement between said cam means and said spool in a timed relation with said periodic means, said smooth side operative to move said spool to said first position at velocities proportional to engine speed while said periodic means is blocking said communicating means, and said steps and said biasing means operative to move said spool in stepped fashion along said path at velocities independent of engine speed while said periodic means is unblocking said communicating means.

An improved metering valve in a pilot injection system of the type including a source of pressurized fuel, a nozzle for delivering the fuel to a cylinder of an internal combustion engine, means for communicating the source with the nozzle, and periodic means for blocking and unblocking the communicating means in a timed relation to the position of the piston in the cylinder, wherein said improved metering valve comprises:

• a valve housing having
• a bore;
• fuel inlet means communicating at one end with said bore and connected at the other end to said source by said communicating means, and
• fuel outlet means defining first opening means at one end communicating with said bore and connected at the other end to said nozzle by said communicating means;
• a spool type valving member slideably moveable in said bore along a path extending from a first position to a second position;
• passage means in said spool defining second opening means blocked from communication with said first opening means when said spool is in said first and second positions, said second opening means operative to traverse said first opening means during movement of said spool from said second position to said first position and operative during said traversing to meter a pilot fuel charge to said outlet means and then a main fuel charge to said outlet means;
• cam means having a lobe smoothly increasing on one side and abruptly decreasing on the other side;
• means biasing said spool toward said lobe;
• and
• means driven at a velocity proportional to engine speed and effecting relative movement between said cam means and said spool in a timed relation with said periodic means, said smoothly increasing side operative to move said spool to said first position at velocities proportional to engine speed while said periodic means is blocking said communicating means, and said abruptly decreasing side and said biasing means operative to move said spool from said first position to said second position at velocities independent of engine speed while said periodic means is unblocking said communicating means, whereby said second opening means traverse said first opening means at velocities independent of engine speed.

A fluid metering valve comprising:

• a valve housing having fluid inlet means adapted to be connected to a source of fluid pressure and fluid outlet means;
• a valving member disposed for movement in said housing between first and second positions and operative while moving from said second position to said first position to momentarily communicate said inlet means with said outlet means, then momentarily block said communication, and then to again momentarily communicate said inlet means with said outlet means, whereby first and second fluid charges are metered to said outlet means;
• first means for moving said valving member from said second position to said first position;
• and
• second means operative to move said valving member from said first position to said second position and then operative to release said valving member and allow said first means to move said valving member at velocities independent of said second means, while said first and second fluid charges are being metered to said outlet.

In a pilot injection system of the type including a source of pressurized fuel, a nozzle for delivering the fuel to a cylinder of an internal combustion engine, means for communicating the source with the nozzle, and periodic means for blocking and unblocking the communicating means in timed relation to the position of a piston in the cylinder, wherein the improvement comprises:

• a valve housing having a fuel inlet port connected to said source by said communicating means and a fuel outlet port connected to said nozzle by said communicating means;
• a valving member disposed for movement in said housing between first and second positions and operative while moving from said second position to said first position to meter a pilot fuel charge to said outlet port and then a main fuel charge to said outlet port;
• first means for moving said valving member from said second position to said first position;
• and
• second means operative to move said valving member from said first position to said second position while said periodic means blocks said communicating means and then operative to release said valving member and allow said first means to move said valving member from said second position to said first position while said periodic means unblocks said communicating means and at velocities independent of engine speed while said pilot and main fuel charges are being metered to said outlet port.