JPS6115233Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to measures for improving the cooling performance of an internal combustion engine equipped with an oil jet for piston cooling.

In recent years, in the case of internal combustion engines, which have been subjected to high loads and high speeds, the heat load on the pistons has become considerably large, and cooling with cooling water alone is insufficient, so oil (lubricating oil) is sprayed onto the back of the pistons to cool the pistons. More and more models are equipped with oil jets.

However, in engines equipped with such oil jets, the pistons are cooled by oil injection from the oil jet even when the engine is not sufficiently warmed up, especially for a while after a cold start, so the combustion chamber temperature decreases. This has disadvantages such as slowing down the warm-up time and causing frequent white smoke due to low-temperature incomplete combustion of the fuel.

The present invention has been devised in view of these conventional drawbacks, and has a simple structure. When the engine is low temperature, the direction of oil injection from the oil jet is directed away from the back surface of the piston and toward the vicinity of the lower end of the cylinder liner, thereby preventing supercooling of the piston. To provide an oil jet for an internal combustion engine, which is configured such that the piston is appropriately cooled by controlling the piston, and directing the oil injection direction of the oil jet toward the back surface of the piston after completion of warm-up.

The present invention will be described in detail below based on embodiments shown in the drawings.

In FIG. 1, the base end of a nozzle tube 3 formed of a bimetallic plate is connected to the lower end of a tubular oil jet main body 2 which is connected to and screwed into an oil gear gallery 1a in a cylinder block 1. The nozzle tube 3 is integrally formed by welding different types of metal members divided into upper and lower parts,
The coefficient of thermal expansion of the lower metal member 3a is greater than that of the upper metal member 3b, and its free end is directed toward the bottom of the cylinder liner 4 wall when the temperature is low, but as the temperature rises, it deforms to warp upward. The piston 5 is configured to face the back surface of the piston 5 as shown by the chain line in the figure.

With this configuration, when the engine temperature is less than a predetermined value, oil is injected to the bottom of the cylinder liner 4 wall by the nozzle tube 3 directed toward the bottom of the cylinder liner 4 wall, but not to the back surface of the piston 5.

Therefore, overcooling of the piston 5 by the injected oil is prevented, the generation of white smoke due to a decrease in the temperature of the combustion chamber can be suppressed, and the warm-up time can be shortened.

When the cylinder block wall temperature and oil temperature rise above a predetermined value, the nozzle tube 3 is directed toward the back surface of the piston 5 due to deformation due to the difference in thermal expansion coefficient between the upper and lower metal members, so oil is injected onto the back surface of the piston 5. As a result, the piston 5 can be cooled as necessary and sufficiently, and good cooling performance can be maintained.

FIG. 2 shows another embodiment of the present invention, in which an oil jet made of a bimetallic plate is mounted on the wall of the cylinder block 1 in the vicinity of a nozzle 11 made of a rigid member of an oil jet held with the oil injection direction directed toward the back surface of the piston 5. The injection direction control member 12 is attached with its lower end fixed.

The oil injection direction control member 12 curves in an arched manner so as to cover the upper part of the injection port of the nozzle 11 when the temperature is low, but as the temperature rises, it deforms so as to approach the inner wall of the cylinder liner 4 as shown by the chain line in the figure, and the nozzle 11 Open the upper part of the injection port.

Therefore, if the cylinder block 1 wall temperature and oil temperature are less than predetermined values, the oil jet nozzle 1
Since the oil injected from the piston 1 collides with the oil injection direction control member 12 and the injection direction is bent, no oil is injected to the back surface of the piston 5.

Furthermore, when the temperature of the oil injection direction control member 12 itself rises as the wall temperature of the cylinder block 1 and the oil temperature rise, the upper end of the oil injection direction control member 12 moves in the direction approaching the inner wall of the cylinder liner 4 as described above. Since the nozzle 11 is deformed and the injection port of the nozzle 11 is opened, oil injected from the injection port is sprayed onto the back surface of the piston 5.

Therefore, in this configuration, as in the embodiment described above, when the engine is at low temperature, the piston 5 is prevented from being overcooled by the oil injection, and after warm-up is completed, the piston 5 is appropriately cooled by the injection oil to obtain good cooling performance. be able to.

As explained above, according to the present invention, the direction of oil injection from the oil jet is changed according to the engine temperature, and when the temperature is low, cooling of the piston with the injection oil is stopped, and when the temperature is above a predetermined temperature, cooling of the piston with the injection oil is started. With this configuration, it is possible to suppress the generation of polluted exhaust gas such as white smoke, and it is also possible to improve the cooling performance of the engine by shortening the warm-up time. Furthermore, since the configuration is simple, it can be implemented at low cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part showing a first embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view of a main part showing a second embodiment of the present invention. 2... Oil jet body, 3... Nozzle tube, 4... Cylinder liner, 5... Piston, 11... Nozzle, 12... Oil injection direction control member.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In an internal combustion engine equipped with an oil jet that cools the piston by injecting oil onto the back surface of the piston, when the oil injection direction is lower than a predetermined value of the engine temperature, the oil injection direction is removed from the back surface of the piston and the piston is cooled. An oil jet for an internal combustion engine, characterized in that an oil jet direction control member made of a bimetallic material that deforms due to temperature sensing is provided near the lower end of a liner so as to direct the oil jet direction toward the back surface of the piston when the temperature exceeds a predetermined value. (2) An oil jet for an internal combustion engine according to claim 1, wherein the oil injection direction control member is a nozzle tube formed of a bimetallic material at the tip of the oil jet. (3) The oil injection direction control member is fixed to the cylinder block wall close to the oil jet, and when the engine temperature is low, it covers the upper part of the oil injection port of the oil jet so that the injection direction is removed from the back of the piston, and when the engine temperature exceeds a predetermined temperature, it deforms and injects oil. An oil jet for an internal combustion engine according to claim 1, which is formed by opening the upper part of the mouth and spraying oil onto the back surface of the piston.