Hydraulic system having a variable delivery pump

A hydraulic system including:

• a low pressure pump having an inlet connected to a source of liquid;
• a high pressure pump with an outlet connected to a high pressure reservoir of said liquid, and having a rotating shaft with a cam that defines a fixed displacement distance with each rotation of said shaft, and further having at least one reciprocable plunger;
• a supply passage extending between an outlet of said low pressure pump and an inlet of said high pressure pump;
• at least one hydraulically actuated device with an inlet connected to said high pressure reservoir;
• an output control mechanism capable of controlling a volume rate of said liquid delivered from said high pressure pump to said high pressure reservoir, and including an electronically controlled flow restriction valve positioned in said supply passage;
• and
• said at least one reciprocable plunger retracting less than said fixed displacement distance during each rotation of said shaft when said flow restriction valve is at least partially closed.

A hydraulic subsystem including:

• an engine including a lubricating oil sump;
• a low pressure pump attached to said engine and having an inlet connected to said lubricating oil sump;
• a high pressure pump attached to said engine with an outlet connected to a high pressure common rail, and having a rotating shaft with a cam that defines a fixed displacement distance with each rotation of said shaft, and further having a plurality of reciprocable plungers distributed around said shaft and lying in a plane;
• an oil supply passage extending between an outlet of said low pressure pump and an inlet of said high pressure pump;
• a plurality of hydraulically actuated devices with inlets connected to said high pressure common rail and outlets connected to said lubricating oil sump;
• an output control mechanism capable of controlling a volume rate of said oil delivered from said high pressure pump to said high pressure common rail, and including an electronically controlled flow restriction valve positioned in said oil supply passage;
• and
• said plurality of reciprocable plungers retracting less than said fixed displacement distance during each rotation of said shaft when said flow restriction valve is at least partially closed.

A variable delivery liquid pump system including:

• a housing defining an inlet, an outlet and a plunger bore;
• a rotating shaft;
• a plunger slidably positioned in said plunger bore and being capable of sliding a fixed displacement distance with each rotation of said shaft;
• a supply of liquid at a supply pressure attached to said inlet by a supply passage;
• and
• an output control mechanism that includes an electronically controlled flow restriction valve positioned in said supply passage, and said plunger retracting less than said fixed displacement distance during each rotation of said shaft when said flow restriction valve is at least partially closed.