Water-cooled internal combustion engine for vehicle

Abstract

The invention provides a water-cooled internal combustion engine for a vehicle. A water jacket allowing the cooling water to circulate is formed on an internal combustion engine main body having a cylinder cover. A thermostat is installed on the internal combustion engine main body and controls according to a state of the cooling water which is discharged from the water jacket and guided to a radiator side and the state of that guided to a bypass path side; the thermostat is equipped on the cylinder cover and forms at least a part of a bypass path on the internal combustion engine main body and avoids the heat from the internal combustion engine main body from influencing the cooling water circulating in the bypass path as much as possible. The thermostat (84) is equipped on the cylinder cover (27). A part of the bypass path (83) is adjacent to an air inlet (45). Viewing along the axial direction of a cylinder hole (40), a part of the bypass path (83) extends in a direction orthogonalto the air inlet (45) and the bypass path and the air inlet (45) are overlapped on the cylinder cover.

Description

technical field [0001] The present invention relates to a vehicle water-cooled internal combustion engine, wherein the internal combustion engine main body has: a cylinder block having a cylinder bore in which a piston is freely slidably fitted; The chamber is combined with the cylinder block, and is provided with an air inlet that can communicate with the combustion chamber. On the main body of the internal combustion engine, a water jacket for circulating cooling water is formed, and a thermostat is installed on the main body of the internal combustion engine. The thermostat controls the state of guiding the cooling water drawn out from the water jacket to the radiator side and the state of guiding the cooling water to the side of the bypass passage that detours around the radiator according to the temperature of the cooling water. Background technique [0002] Patent Document 1 discloses a water-cooled internal combustion engine. A water pump and a thermostat disposed clo...

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Problems solved by technology

[0004] However, in the invention disclosed in the above-mentioned Patent Document 1, during the warm-up operation of the internal combustion engine, the temperature of the cooling water flowing into the thermostat from the bypass passage cannot accurately reflect the temperature of the cooling water in the water jacket. If the water temperature fluctuates greatly, the temperature control characteristics of the thermostat may deviate from the specified characteristics.

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