Oil supply system for an engine

摘要

An oil supply system for a reciprocating piston internal combustion engine is disclosed in which the supply of oil to piston cooling jets is controlled by pressure operated valves designed to open at a pre-defined valve opening pressure. The pressure of oil supplied by a pump is controlled to be below this pre-defined valve opening pressure during operation of the engine in which piston cooling is not required, and the pressure of oil is controlled to above the pre-defined valve opening pressure when piston cooling is required. The control of the pump is by an electronic control unit based upon a combination of engine speed and engine load.

主权项

1. A method in an engine, comprising:
adjusting, responsive to engine speed, oil pressure inversely with engine speed by adjusting a solenoid valve, wherein adjusting the solenoid valve comprises,
in a low-pressure mode of operation of a variable flow rate oil pump, adjusting the solenoid to hydraulically couple an oil galley with a first inlet of a spool valve via a secondary feedback supply, to permit oil flow from the oil galley to the first inlet of the spool valve, wherein an outlet of the spool valve is hydraulically coupled with an inlet of the variable flow rate oil pump and a second inlet of the spool valve is permanently hydraulically coupled with the oil galley via a primary feedback supply; andin a high-pressure mode of operation of the variable flow rate oil pump, adjusting the solenoid to block oil flow from the oil galley to the first inlet of the spool valve; selectively routing oil through the oil galley to a piston cooling jet via a pressure-operated valve responsive to the adjusted oil pressure; and responsive to identified degradation of the solenoid valve, increasing the oil pressure irrespective of engine speed to supply oil cooling jet operation, wherein a position of the solenoid valve is adjusted to operate the variable flow rate oil pump in the low-pressure mode irrespective of engine load when engine speed is below a lower limiting value.