Claims:We Claim

1. A lubrication oil circuit (10) of a fuel injection system, said lubrication oil circuit (10) comprising:
a lubrication oil tank (12);
a lubrication oil pump (14) coupled in flow communication downstream from said lubrication oil tank (12), said lubrication oil pump (14) adapted to receive lubrication oil that is supplied from said lubrication oil tank (12);
a lubrication oil supply path (16), an upstream end of said lubrication oil supply path (16) in flow communication with said lubrication oil pump (14), a downstream end of said lubrication oil supply path (16) in flow communication with an engine (18); characterized in that
a fuel control unit (20) in flow communication with the lubrication oil supply path (16) and positioned between said lubrication oil pump (14) and said engine (18), said fuel control unit (20) adapted to control a flow of pressurized lubrication oil from said lubrication oil pump (14) to said engine (18).
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to a fuel control unit, and more specifically to a fuel control unit that is integrated in a lubrication oil circuit of a fuel injection system.

Background of the invention
[0002] JP Patent Application Number 63272921 A describes preventing excessive feeding of lubrication oil in the captioned device in which lubricating oil is fed independently into each cylinder of a plurality of cylinders by providing a control means for the feeding quantity of lubricating oil to each cylinder and reducingly correcting the quantity of lubricating oil fed into a cylinder having a large rotor swinging quantity. Lubrication oil is discharged out of a metering oil pump which is driven by a stepper motor and is independently fed into port oil feeding ports via lubricating oil feeding passages and into direct oil feeding nozzles via lubricating oil feeding passages respectively. In such a lubricating oil feeding device, flow-rate controlling electromagnetic throttle valves are provided midway in lubricating oil feeding passages respectively. In the case of a three-cylinder rotary piston engine, for example, considering a cylinder in the center part having a relatively low supporting rigidity and swingable at the time of eccentric rotor, the quantity of lubrication oil that is fed into the cylinder is controlled to be reducingly corrected.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a schematic diagram of a lubrication oil circuit of a fuel injection system.

Detailed description of the embodiments
[0004] Figure 1 illustrates a lubrication oil circuit 10 of a fuel injection system. The lubrication oil circuit 10 comprises a lubrication oil tank 12 and a lubrication oil pump 14 coupled in flow communication downstream from the lubrication oil tank 12, the lubrication oil pump 14 adapted to receive lubrication oil that is supplied from the lubrication oil tank 12. A lubrication oil supply path 16, an upstream end of the lubrication oil supply path 16 in flow communication with the lubrication oil pump 14, a downstream end of the lubrication oil supply path 16 in flow communication with an engine 18. A fuel control unit 20 is in flow communication with the lubrication oil supply path 16 and positioned between the lubrication oil pump 14 and the engine 18, the fuel control unit 20 adapted to control a flow of pressurized lubrication oil from the lubrication oil pump 14 to the engine 18.

[0005] The lubrication oil circuit 10 of the fuel injection system comprises a lubrication oil tank 12. A lubrication oil pump 14 is positioned downstream from the lubrication oil tank 12 and receives lubrication oil that is discharged from the lubrication oil tank 12. In the exemplary embodiment, an upstream end of a conduit 15 is in flow communication with an outlet of the lubrication oil tank 12 and receives lubrication oil that is discharged from the lubrication oil tank 12. A downstream end of the conduit 15 is in flow communication with the lubrication oil pump 14 and supplies pressurized lubrication oil to the lubrication oil pump 14. From an outlet of the lubrication oil pump 14, a lubrication oil supply path 16 supplies pressurized lubrication oil that is pressurized by the lubrication oil pump 14 to an engine 18. More specifically, an upstream end of the lubrication oil supply path 16 is in flow communication with an outlet of the lubrication oil pump 14. A downstream end of the lubrication oil supply path 16 is in flow communication with the engine 18 and delivers pressurized lubrication oil that is supplied from the lubrication oil pump 14 to the engine 18.

[0006] A fuel control unit 20 is in flow communication with the lubrication oil supply path 16 and receives the lubrication oil that is supplied from the lubrication oil pump 14. More specifically, the fuel control unit 20 is positioned between the lubrication oil pump 14 and the engine 18. In an exemplary embodiment, the downstream end of the lubrication oil supply path 16 is in flow communication with an engine bearing, an engine camshaft that opens and closes the fuel inlet and outlet valves respectively, rotating and reciprocating components of the engine, a valve rocker, a push rod, a tappet valve rocker, crankshaft drillings, crankshaft connecting rod bearings, a big end bearing, a gear driver, a high pressure pump roller tappet, the high pressure pump bearings, and a camshaft of the high pressure fuel pump where oil lubrication is required to be supplied.

[0007] In the exemplary embodiment, an engine control unit (not shown) is in electronic communication with the fuel control unit 20 and controls a flow of lubrication oil out of the fuel control unit 20 depending on the requirement. The fuel control unit 20 is adapted to control a flow of pressurized lubrication oil from the oil pump 14 to the engine 18 via the lubrication oil supply path 16. More specifically, depending on the lubrication oil requirement of the engine bearing, the engine camshaft that opens and closes the fuel inlet and outlet valves respectively, rotating and reciprocating components of the engine, the valve rocker, the push rod, the tappet valve rocker, crankshaft drillings, crankshaft connecting rod bearings, the big end bearing, the gear driver, the high pressure pump roller tappet, the high pressure pump bearings, and the camshaft of the high pressure fuel pump where oil lubrication is required, the engine control unit 20 controls an actuation of the fuel control unit to deliver the precise quantity of lubrication oil to the respective engine components based on the demanded quantity of lubrication oil.

[0008] A working of the lubrication oil circuit 10 of the fuel injection system is described as an example. Lubrication oil is supplied from a lubrication oil tank 12 to the lubrication oil pump 14 via the conduit 15 due to the suction that is created in the lubrication oil pump 14. From the lubrication oil pump 14, the lubrication oil is pressurized and delivered from the outlet of the lubrication oil pump 14 to the fuel control unit 20 via the lubrication oil supply path 16. The fuel control unit 20 is adapted to regulate a flow of pressurized lubrication oil from the lubrication oil pump 14 to the engine 18 via the lubrication oil supply path 16. More specifically, depending on the lubrication oil requirement of the engine bearing, the engine camshaft that opens and closes the fuel inlet and outlet valves respectively, rotating and reciprocating components of the engine, the valve rocker, the push rod, the tappet valve rocker, crankshaft drillings, crankshaft connecting rod bearings, the big end bearing, the gear driver, the high pressure pump roller tappet, the high pressure pump bearings, and a camshaft of the high pressure fuel pump where oil lubrication is required to be supplied, the precise quantity of lubrication oil is regulated by the fuel control unit to each of these engine components. The engine control unit controls an actuation of the fuel control unit 20 to deliver the precise quantity of lubrication oil to the respective engine components based on the demanded quantity of lubrication oil. When the lubrication oil is required by the engine bearing, the engine camshaft that opens and closes the fuel inlet and outlet valves respectively, rotating and reciprocating components of the engine, the valve rocker, the push rod, a tappet valve rocker, crankshaft drillings, crankshaft connecting rod bearings, the big end bearing, the gear driver, the high pressure pump roller tappet, the high pressure pump bearings, and the camshaft of the high pressure fuel pump, the fuel control unit 20 precisely regulates a required quantity of lubrication oil that is delivered from the conduit 15, the oil pump 14, and the lubrication oil supply path 16 to each of these engine components.

[0009] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.