Lubrication system for vehicle engine

1. A lubrication system for a vehicle combustion engine, the lubrication system comprising:

an oil pump configured to supply a lubricating oil;

an oil filter disposed downstream of the oil pump in a flow direction of the lubricating oil and configured to clean the lubricating oil;

an oil cooler disposed downstream of the oil filter and configured to cool the lubricating oil, the oil filter and the oil cooler being disposed on a front surface of a crankcase of an engine body side by side in a first direction which engine body in a die molded product,

a first lubrication passage connected to an outflow passage of the oil cooler and extending in the first direction;

a second lubrication passage disposed parallel to at least one passage connected to one of the oil filter and the oil cooler, the second lubrication passage being connected to the first lubrication passage and extending at a front surface side of the engine body; and

a third lubrication passage connected to the second lubrication passage and extending in a second direction from the second lubrication passage at the front surface side of the engine body with respect to the first lubrication passage, the second direction being different from the first direction, wherein

an inflow passage and an outflow passage for the oil filter and an inflow passage and an outflow passage for the oil cooler are formed in a front wall of the crankcase made of metal and

the first lubrication passage and the filter-cooler communication passage extend in the crankcase in a widthwise direction of a vehicle, where incoming wind, when the vehicle is moving, collides against the front wall of the crankcase,

the second lubrication passage is disposed between the oil filter and the oil cooler in the vehicle widthwise direction, and is overlapped with the oil filter at a front view, and

the second lubrication passage is disposed above the inflow passage and the outflow passage for the oil filter with respect to a height position of the engine.

2. The lubrication system for the vehicle combustion engine as claimed in claim 1 , wherein an outflow passage and an inflow passage for the one of the oil filter and the oil cooler are disposed parallel to the second lubrication passage.

3. The lubrication system for the vehicle combustion engine as claimed in claim 1 , further comprising a closing member closing an end portion of the second lubrication passage, the closing member being disposed inward of one of the oil filter and the oil cooler and being inserted to a front end portion of the second engine lubrication passage.

4. The lubrication system for the vehicle combustion engine as claimed in claim 1 , wherein:

the third lubrication passage is a passage for spraying the lubricating oil toward a piston;

the first direction is a vehicle widthwise direction and the second direction is a vertical direction; and

the third lubrication passage extends upward from the second lubrication passage and extends within a front wall of a cylinder of the engine body in the vehicle widthwise direction.

5. The lubrication system for the vehicle combustion engine as claimed in claim 1 , wherein

a discharge passage for the oil pump is connected to one of inflow passages for the oil filter and the oil cooler,

an outflow passage for the oil filter and the inflow passage for the oil cooler communicate with each other through a filter-cooler communication passage,

an outflow passage for the oil cooler communicates with the second lubrication passage through a part of the first lubrication passage,

the filter-cooler communication passage and the part of the first lubrication passage are provided parallel to each other,

the first direction is a vehicle widthwise direction and the second direction is a vertical direction,

the first engine lubrication passage is disposed above the filter-cooler communication passage, and

the third lubrication passage extends upward from the second lubrication passage.

6. The lubrication system for the vehicle combustion engine as claimed in claim 5 , wherein

the oil filter and the oil cooler are disposed on a front surface of a crankcase of the engine body,

the inflow passage and the outflow passage for the oil filter and the inflow passage and the outflow passage for the oil cooler are formed in a front wall of the crankcase, and

the part of the first lubrication passage and the filter-cooler communication passage extend in the crankcase in a widthwise direction of a vehicle,

the second engine lubrication passage is disposed between the oil filter and the oil cooler in the vehicle widthwise direction, and is overlapped with the oil filter at a front view, and

the second engine lubrication passage is disposed above the inflow passage and the outflow passage for the oil filter.

7. The lubrication system for the vehicle combustion engine as claimed in claim 1 , further comprising:

a sub lubrication passage which supplies the lubricating oil to a transmission for a vehicle; and

a filter-cooler communication passage through which an outflow passage for the oil filter and the inflow passage for the oil cooler communicate with each other, the filter-cooler communication passage being fluidly connected to the sub lubrication passage.

8. The lubrication system for a vehicle combustion engine as claimed in claim 5 wherein lubrication passages are formed within the crankcase and the cylinder block and provide lubricating oil to a supercharger, gear teeth of a planetary gear, a power transmission sprocket, a one way clutch, a starter motor gear, balancer shaft, a power transmission, crankshaft bearings, pistons, and wall surfaces of cylinders.

9. The lubrication system for a vehicle combustion engine as claimed in claim 8 including an aluminum die cast engine body.