Internal combustion engine cooling system

1. An internal combustion engine comprising:

a crankcase;

a crankshaft disposed in the crankcase;

a cylinder block connected to the crankcase, the cylinder block having a first side, a second side, and at least one cylinder;

at least one piston disposed in the at least one cylinder, the at least one piston being operatively connected to the crankshaft;

a cylinder head assembly connected to the cylinder block; and

a cooling system for cooling at least a portion of the engine, the cooling system having:

a first cooling jacket for cooling the first side of the cylinder block;

a second cooling jacket for cooling the second side of the cylinder block;

a cylinder head cooling jacket for cooling the cylinder head assembly;

a coolant inlet fluidly communicating with the first cooling jacket;

a coolant outlet fluidly communicating with the second cooling jacket;

a coolant pump fluidly communicating with the coolant inlet for pumping coolant through the cooling system; and

an oil cooler fluidly communicating with the first cooling jacket and the coolant pump,

the first cooling jacket fluidly communicating with the cylinder head cooling jacket, the cylinder head cooling jacket fluidly communicating with the second cooling jacket;

coolant flowing in the cooling system flows from the coolant inlet to the first cooling jacket, from the first cooling jacket to the cylinder head cooling jacket, from the cylinder head cooling jacket to the second cooling jacket, and from the second cooling jacket to the coolant outlet, and

a portion of the coolant flowing in the first cooling jacket flows to the oil cooler, and from the oil cooler to the coolant pump.

2. The engine of claim 1 , wherein the coolant inlet is on the first side of the engine and the coolant outlet is on the second side of the engine.

3. The engine of claim 1 , wherein the cooling system also has a heat exchanger for cooling coolant flowing in the cooling system; and

wherein coolant flowing in the cooling system flows from the coolant outlet to the heat exchanger, from the heat exchanger to the coolant pump, and from the coolant pump to the coolant inlet.

4. The engine of claim 3 , wherein the cooling system also has a thermostat, the thermostat has a thermostat inlet fluidly communicating with the coolant outlet, a first thermostat outlet fluidly communicating with the heat exchanger, and a second thermostat outlet fluidly communicating with the coolant pump; and

wherein coolant flowing in the cooling system flows from the coolant outlet to the thermostat inlet, from the thermostat inlet to the first thermostat outlet when the coolant is above a predetermined temperature, and from the thermostat inlet to the second thermostat outlet when the coolant is below the predetermined temperature.

5. The engine of claim 1 , wherein the first and second cooling jackets are integrally formed in the cylinder block; and

the cylinder head cooling jacket is integrally formed in the cylinder head assembly.

6. The engine of claim 1 , further comprising:

at least one intake valve disposed in the cylinder head assembly above the at least one cylinder on an intake side of the engine; and

at least one exhaust valve disposed in the cylinder head assembly above the at least one cylinder on an exhaust side of the engine.

7. The engine of claim 6 , wherein the first side of the cylinder block is on the exhaust side of the engine and the second side of the cylinder block is on the intake side of the engine.

8. A cooling system for an internal combustion engine comprising:

a first cooling jacket for cooling a first side of an engine cylinder block;

a second cooling jacket for cooling a second side of the engine cylinder block;

a cylinder head cooling jacket for cooling a cylinder head assembly of the engine;

a coolant inlet fluidly communicating with the first cooling jacket;

a coolant outlet fluidly communicating with the second cooling jacket;

a coolant pump fluidly communicating with the coolant inlet for pumping coolant through the cooling system; and

an oil cooler fluidly communicating with the first cooling jacket and the coolant pump,

the first cooling jacket fluidly communicating with the cylinder head cooling jacket, the cylinder head cooling jacket fluidly communicating with the second cooling jacket;

coolant flowing in the cooling system flows from the coolant pump to the coolant inlet, from the coolant inlet to the first cooling jacket, from the first cooling jacket to the cylinder head cooling jacket, from the cylinder head cooling jacket to the second cooling jacket, and from the second cooling jacket to the coolant outlet, and

a portion of the coolant flowing in the first cooling jacket flows to the oil cooler, and from the oil cooler to the coolant pump.

9. The cooling system of claim 8 , further comprising a heat exchanger for cooling coolant flowing in the cooling system; and

wherein coolant flowing in the cooling system flows from the coolant outlet to the heat exchanger, and from the heat exchanger to the coolant pump.

10. The cooling system of claim 9 , further comprising a thermostat, the thermostat has a thermostat inlet fluidly communicating with the coolant outlet, a first thermostat outlet fluidly communicating with the heat exchanger, and a second thermostat outlet fluidly communicating with the coolant pump; and

wherein coolant flowing in the cooling system flows from the coolant outlet to the thermostat inlet, from the thermostat inlet to the first thermostat outlet when the coolant is above a predetermined temperature, and from the thermostat inlet to the second thermostat outlet when the coolant is below the predetermined temperature.

11. A method of cooling an internal combustion engine, the engine having a crankcase; a crankshaft disposed in the crankcase; a cylinder block connected to the crankcase, the cylinder block having a first side, a second side, and at least one cylinder; at least one piston disposed in the at least one cylinder, the at least one piston being operatively connected to the crankshaft; a cylinder head assembly connected to the cylinder block; a coolant pump; and an oil cooler; the method comprising:

pumping coolant to a first cooling jacket using the coolant pump for cooling the first side of the cylinder block;

delivering coolant from the first cooling jacket to a cylinder head cooling jacket for cooling the cylinder head assembly;

delivering coolant from the cylinder head cooling jacket to a second cooling jacket for cooling the second side of the cylinder block;

delivering coolant from the first cooling jacket to the oil cooler; and

delivering coolant from the oil cooler to the coolant pump.

12. The method of claim 11 , wherein the engine also has a heat exchanger for cooling the coolant, the method further comprising:

delivering coolant from the second cooling jacket to the heat exchanger; and

delivering coolant from the heat exchanger to the coolant pump.

13. The method of claim 12 , wherein the engine also has a thermostat, the method further comprising:

delivering coolant from the second cooling jacket to the thermostat;

delivering coolant from the thermostat to the heat exchanger when the coolant is above a predetermined temperature; and

delivering coolant from the thermostat to the coolant pump when the coolant is below the predetermined temperature.