Cooling structure for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10323565-B2
Application number	US-201815866189-A
Country	US
Kind code	B2
Filing date	Jan 9, 2018
Priority date	Feb 7, 2017
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

In an internal combustion engine, a thermostat valve for changing over between coolant circulation through a radiator-routing passage to coolant circulation through a bypass passage, is provided with a first valve for opening and closing the radiator-routing passage, and a second valve for opening and closing the bypass passage. The first and second valves and are operable concurrently. A cylinder coolant jacket around cylinder bores of a cylinder portion is partitioned into two in a cylinder axis direction to thereby form a main cylinder coolant jacket on a side of a cylinder head portion and a sub-cylinder coolant jacket on a side of a crankcase portion. The bypass passage is formed partly by the sub-cylinder coolant jacket. The above arrangement expedites warming-up during the engine start and achieves favorable appearance by a simplified structure.

First claim

The invention claimed is:

1. A cooling structure for an internal combustion engine comprising: an engine main unit including a crankcase portion, a cylinder portion, and a cylinder head portion, the cylinder portion and the cylinder head portion having therein a cylinder coolant jacket and a cylinder head coolant jacket, respectively; a coolant pump for circulating coolant through coolant circulation paths formed in the cylinder coolant jacket and the cylinder head coolant jacket, the coolant circulation path paths including a radiator-routing passage by way of a radiator and a bypass passage bypassing the radiator, the radiator-routing passage and the bypass passage returning back to the coolant pump; and a thermostat valve for changing over between coolant circulation through the radiator-routing passage and coolant circulation through the bypass passage, wherein the thermostat valve includes a first valve for opening and closing the radiator-routing passage, and a second valve for opening and closing the bypass passage, the first valve and the second valve being operated concurrently; wherein the cylinder coolant jacket is disposed around a cylinder bore in the cylinder portion and is partitioned into two in a cylinder axis direction to thereby form a main cylinder coolant jacket on a side of the cylinder head portion and a sub-cylinder coolant jacket on a side of the crankcase portion, wherein the coolant pump is connected to the thermostat valve by way of the main cylinder coolant jacket and the cylinder head coolant jacket, and wherein the thermostat valve is connected to the coolant pump by way of the sub-cylinder coolant jacket, which forms a part of the bypass passage bypassing the radiator.

2. The cooling structure for an internal combustion engine according to claim 1 , wherein the main cylinder coolant jacket has a volume greater than a volume of the sub-cylinder coolant jacket.

3. The cooling structure for an internal combustion engine according to claim 2 , wherein the second valve has formed therein a leak passage through which coolant leaks when the second valve is in a closed position.

4. The cooling structure for an internal combustion engine according to claim 2 , wherein the thermostat valve is integrated with the engine main unit.

5. The cooling structure for an internal combustion engine according to claim 2 , wherein
the cylinder portion is disposed to extend superiorly from the crankcase portion;
a starting motor is disposed on the crankcase portion adjacent the cylinder portion; and
the starter motor is disposed on a side of the cylinder bores with part of the sub-cylinder coolant jacket positioned between the cylinder bores and the starter motor.

6. The cooling structure for an internal combustion engine according to claim 1 , wherein the second valve has formed therein a leak passage through which coolant leaks when the second valve is in a closed position.

7. The cooling structure for an internal combustion engine according to claim 6 , wherein the thermostat valve is integrated with the engine main unit.

8. The cooling structure for an internal combustion engine according to claim 6 , wherein
the cylinder portion is disposed to extend superiorly from the crankcase portion;
a starting motor is disposed on the crankcase portion adjacent the cylinder portion; and
the starter motor is disposed on a side of the cylinder bores with part of the sub-cylinder coolant jacket positioned between the cylinder bores and the starter motor.

9. The cooling structure for an internal combustion engine according to claim 1 , wherein the thermostat valve is integrated with the engine main unit.

10. The cooling structure for an internal combustion engine according to claim 6 , wherein:
the cylinder portion includes a plurality of cylinder bores arrayed in series with each other; and
the thermostat valve is disposed adjacent one of outermost cylinder bores disposed on two lateral ends in a direction in which the cylinder bores are arrayed.

11. The cooling structure for an internal combustion engine according to claim 10 , wherein the coolant pump is disposed on a side opposite to the thermostat valve in the direction in which the cylinder bores are arrayed in the internal combustion engine.

12. The cooling structure for an internal combustion engine according to claim 11 , wherein
the cylinder portion is disposed to extend superiorly from the crankcase portion;
a starting motor is disposed on the crankcase portion adjacent the cylinder portion; and
the starter motor is disposed on a side of the cylinder bores with part of the sub-cylinder coolant jacket positioned between the cylinder bores and the starter motor.

13. The cooling structure for an internal combustion engine according to claim 10 , wherein the coolant pump is disposed on a side identical to a side on which the thermostat valve is disposed in the direction in which the cylinder bores are arrayed in the internal combustion engine.

14. The cooling structure for an internal combustion engine according to claim 13 , wherein
the cylinder portion is disposed to extend superiorly from the crankcase portion;
a starting motor is disposed on the crankcase portion adjacent the cylinder portion; and
the starter motor is disposed on a side of the cylinder bores with part of the sub-cylinder coolant jacket positioned between the cylinder bores and the starter motor.

15. The cooling structure for an internal combustion engine according to claim 10 , wherein
the cylinder portion is disposed to extend superiorly from the crankcase portion;
a starting motor is disposed on the crankcase portion adjacent the cylinder portion; and
the starter motor is disposed on a side of the cylinder bores with part of the sub-cylinder coolant jacket positioned between the cylinder bores and the starter motor.

16. The cooling structure for an internal combustion engine according to claim 9 , wherein
the cylinder portion is disposed to extend superiorly from the crankcase portion;
a starting motor is disposed on the crankcase portion adjacent the cylinder portion; and
the starter motor is disposed on a side of the cylinder bores with part of the sub-cylinder coolant jacket positioned between the cylinder bores and the starter motor.

17. The cooling structure for an internal combustion engine according to claim 1 , wherein:
the cylinder portion is disposed to extend superiorly from the crankcase portion;
a starting motor is disposed on the crankcase portion adjacent the cylinder portion; and
the starter motor is disposed on a side of the cylinder bores with part of the sub-cylinder coolant jacket positioned between the cylinder bores and the starter motor.

Assignees

• Honda Motor Co Ltd

Inventors

• Matsushita Koichiro

Classifications

• F01P7/162

  by cutting in and out of pumps · CPC title

• F01P2003/027

  Cooling cylinders and cylinder heads in parallel · CPC title

• F01P3/20

  Cooling circuits not specific to a single part of engine or machine (F01P3/22 takes precedence) · CPC title

• F01P5/10

  Pumping liquid coolant; Arrangements of coolant pumps · CPC title

• F01L1/02

  Valve drive (transmitting-gear between valve drive and valve F01L1/12) · CPC title