Pump assembly, valve and method

An inlet controlled pump assembly for pumping a pressurized liquid, the assembly comprising,

• A) a pump having a body;
• a pump bore in the body;
• a piston in the pump bore;
• a rotary piston drive wherein the piston moves back and forth in the pump bore through pumping and return strokes;
• a pumping chamber in the pump bore;
• an outlet check valve away from the piston to flow pumped liquid from the pumping chamber;
• an inlet port;
• an outlet port;
• a first passage extending from the inlet port through the piston to the pumping chamber during each return stroke of the piston;
• and a second passage extending from the outlet check valve to the outlet port, the pump operable to pump liquid from the outlet port at a pumped outlet pressure;
• B) an inlet throttle valve located in the first passage, the inlet throttle valve including a movable valve member to control the volume of liquid flowed through the first passage to the pumping chamber;
• and
• C) a regulator for the inlet throttle valve to move the valve member in response to the pumped outlet pressure and a determined outlet pressure, the regulator including an input device to receive a signal proportional to a determined outlet pressure, a first connection between the regulator and the inlet throttle valve;
• and a second connection between the second passage and the regulator, wherein the regulator increases the flow of liquid to the pumping chamber when the pressure in the second passage is less than a determined pressure and decreases the flow of liquid to the pumping chamber when the pressure in the second passage is greater than a determined pressure.

A method of controlling the pressure of oil used to actuate hydraulically driven devices in an internal combustion engine, the engine including a high pressure oil pump having a pumping chamber, an inlet passage extending to the pumping chamber;

• an outlet passage extending from the pumping chamber to the devices, and an engine control system for determining a desired pressure of the oil in the outlet passage, comprising the steps of:
• A) flowing oil through the inlet passage and into the pumping chamber at low pressure while maintaining the inlet passage unobstructed adjacent the pumping chamber;
• B) pumping the low pressure oil into the outlet passage to increase the pressure of the oil in the outlet passage;
• C) increasing the flow of low pressure oil into the pumping chamber when the pressure of the oil in the outlet passage is lower than the desired pressure;
• D) decreasing the flow of low pressure oil into the pumping chamber when the pressure of the oil in the outlet passage is higher than the desired pressure;
• and
• E) expanding the oil in the outlet passage to actuate the devices.

A method of controlling the pressure of a pumped liquid using a pump having a pumping chamber, a piston movable back and forth along the pumping chamber through pumping and return strokes, a drive for moving the piston in the pumping chamber, an inlet passage leading to the pumping chamber, an outlet passage extending away from the pumping chamber and a poppet valve located between the pumping chamber and the outlet passage, comprising the steps of:

• A) flowing low pressure liquid through the first passage to the pumping chamber during return strokes of the piston, and maintaining the first passage leading into the pumping chamber open from substantially the beginning of the return stroke to substantially the end of the return stroke;
• B) pumping the low pressure liquid past the poppet valve and into the second passage during pumping strokes of the piston to increase the pressure of the liquid in the high pressure passage;
• C) increasing the flow of low pressure liquid to the pump when the pressure of the liquid in the second passage is lower than a desired pressure;
• and
• D) decreasing the flow of low pressure liquid to the pump when the pressure of the liquid in the second passage is higher than a desired pressure.

An inlet throttle valve for controlling inlet flow of hydraulic fluid to a pump supplying high pressure hydraulic fluid to actuate electronically controlled, hydraulically driven devices in an internal combustion engine;

• the inlet throttle valve comprising a body;
• a valve passage in the body having opposed ends, a hydraulic fluid inlet port opening into the passage;
• a hydraulic fluid outlet port opening into the passage;
• one of said ports extending through the circumferential wall of the passage;
• the inlet port to be connected to a source of low pressure hydraulic fluid;
• the outlet port to be connected to a pump;
• a valve member including a wall, said wall having a sliding fit in the passage and moveable along the passage across said one port to throttle flow of hydraulic fluid through the port and to the pump;
• a spring biasing the valve member along the passage toward one end of the passage;
• and force exerting means for biasing the valve member along the passage away from said one end of the passage in response to the difference between the output pressure of the pump and a desired output pressure;
• said valve having a fully open, start position when the valve member is adjacent said one end of the passage and partially open, operating positions when the valve member is away from such end of the passage.