Oil pressure switch, apparatus for diagnosing piston cooling oil jet, and method of controlling the same

An apparatus for diagnosing a failure in a piston oil cooling jet having an oil path through which oil flows for cooling a piston, the apparatus comprising:

• a solenoid valve selectively opening and closing the oil path;
• an oil pressure switch connected in the oil path, outputting an output signal through a switch output terminal according to a pressure of oil that flows through the oil path, and to which a parallel resistor is electrically connected to a front end of the switch output terminal;
• and
• a controller having a control resistor of which a first end is electrically connected with a control power and a second end is electrically connected with the switch output terminal of the oil pressure switch through a connector,
• wherein the controller controls opening and closing of the solenoid valve and determines whether the solenoid valve and the oil pressure switch malfunction based on an input voltage of a control input terminal of the controller.

A method for diagnosing a failure in a piston cooling jet, which includes:

• a solenoid valve selectively opening and closing an oil path;
• an oil pressure switch outputting an output signal through a switch output terminal according to opening and closing of the solenoid valve and outputting an output signal through a switch output terminal that is electrically connected with parallel resistors;
• and a controller that includes a control resistor of which a first end is electrically connected with a control power and a second end is electrically connected with the switch output terminal of the oil pressure switch through a connector, the method comprising steps of:
• determining, by a controller, whether an input voltage of a control input terminal of the controller is within a predetermined range from a first voltage;
• determining, by the controller, whether the input voltage of the control input terminal is within a predetermined range from a second voltage;
• determining, by the controller, whether the input voltage of the control input terminal is within a predetermined range from a third voltage when a close signal is output to close the solenoid valve;
• determining, by the controller, whether the input voltage of the control input terminal is within in a predetermined range from a fourth voltage by the controller when an open signal that controls the solenoid valve to be opened is output;
• and
• determining, by the controller, whether the solenoid valve and the oil pressure switch malfunction from the input voltage of the control input terminal.