Electrically controlled hydraulic valve calibration method and system

A system for calibrating an electrically controlled hydraulic valve having a known relationship between flow rate through the valve and displacement of a valve element, comprising:

• a first and a second electrically controlled hydraulic valve disposed in parallel with each other, wherein the second electrically controlled hydraulic valve is to be calibrated;
• a hydraulic fluid pump configured to pump hydraulic fluid from a fluid source through the first and second electrically controlled hydraulic valves;
• and
• a controller configured to:
• actuate the second electrically controlled hydraulic valve to be calibrated to move the valve element to a position adjacent the inlet port so that the valve just opens enough to permit flow through the inlet port;
• actuate the second electrically controlled hydraulic valve to move the valve element to a position permitting flow through the inlet port;
• ascertain a first current level for actuating the second electrically controlled hydraulic valve to move the valve element to the position adjacent the inlet port, and a first displacement of the valve element responsive to the first current level;
• ascertain a second current level for actuating the second electrically controlled hydraulic valve to move the valve element from the position adjacent the inlet port to the position permitting flow through the inlet port;
• ascertain a first flow rate through the first electrically controlled hydraulic valve to determine a second flow rate through the second electrically controlled hydraulic valve;
• correlate the determined second flow rate through the second electrically controlled hydraulic valve with a second displacement of the valve element thereof based on the known relationship between flow rate through the valve and displacement of the valve element;
• and
• establish a relationship between current and displacement associated with the second electrically controlled hydraulic valve based on at least the first and the second current levels, and the first and the second displacements.

A machine, comprising:

• an engine;
• a hydraulic system;
• an implement system;
• and
• a system for calibrating an electrically controlled hydraulic valve having a known relationship between flow rate through the valve and displacement of a valve element, the system including:
• a first electrically controlled hydraulic valve having a known correlation between current and flow rate;
• a second electrically controlled hydraulic valve to be calibrated and disposed in parallel with the first electrically controlled hydraulic valve;
• a hydraulic fluid pump configured to pump hydraulic fluid from a fluid source through the first and second electrically controlled hydraulic valve;
• and
• a controller configured to:
• actuate the second electrically controlled hydraulic valve to move the valve element to a position adjacent the inlet port so that the valve just opens enough to permit flow through the inlet port;
• actuate the second electrically controlled hydraulic valve to move the valve element to a position permitting flow through the inlet port;
• ascertain a first current level for actuating the second electrically controlled hydraulic valve to move the valve element to the position adjacent the inlet port;
• ascertain a first displacement of the valve element of the second electrically controlled hydraulic valve in response to the first current level;
• ascertain a second current level for actuating the second electrically controlled hydraulic valve to move the valve element from the position adjacent the inlet port to the position permitting flow through the inlet port;
• ascertain a first flow rate through the first electrically controlled hydraulic valve;
• determine a second flow rate through the second electrically controlled hydraulic valve;
• correlate the determined second flow rate through the second electrically controlled hydraulic valve with a second displacement of the valve element thereof based on the known relationship between flow rate through the valve and displacement of the valve element;
• and
• establish a relationship between current and displacement associated with the second electrically controlled hydraulic valve based on at least one of the first and the second current levels, and the first and the second displacements.