JPH03168317A - Oil cooling device for piston - Google Patents

Abstract

PURPOSE:To cool a piston with the sufficient quantity of oil during high speed rotation and to timely jet the proper quantity of the oil to the piston during low speed rotation by providing each of parallel oil passages leading to an oil jet pipe with a valve. CONSTITUTION:Two parallel oil passages 11, 12 are provided in a space from an oil hole 20 in a cylinder block 16 to an oil jet valve 1. The oil passage 11 is provided with a rotary valve 13 to open when a piston takes its position at the bottom dead center, and the oil passage 12 is provided with an electromagnetic valve 14 to close when engine speed is low. Thus the valve 14 is closed in the case of the low engine speed, and the rotary valve 13 is opened when the piston takes its position at the bottom dead center to jet the oil to the back face of the piston. In the case of medium or high engine speed, the valve 14 is also opened for jetting the large quantity of the oil. Thus the cooling and lubricating effect of the oil is increased in the case of the medium or high engine speed, and the oil is certainly jetted in the case of the low engine speed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a piston oil cooling device.

[Conventional technology]

Conventionally, one method of cooling engine pistons is
As shown in FIG. 3, an oil pump (not shown) is connected to an oil jet 10 fixed to a cylinder block 16.
A method of cooling and lubricating the piston by continuously jetting oil under pressure onto the back surface of the piston 30 is used. In this case, oil is once pumped into the oil hole 20 by the oil pump, and when the oil pressure therein exceeds a certain pressure, the steel ball 3 in the oil jet 10 presses the spring 4 to open the oil jet valve 1. Oil is injected from the nozzle 5 toward the back surface of the piston 30 to cool and lubricate the piston from the back surface. This oil injection is performed when the oil pressure of the oil forced into the oil hole 20 exceeds the biasing force of the spring 4, and the steel ball 3 is pushed down. After the injection, the oil jet valve l is closed, and when the pressure inside the oil hole 20 increases, the next injection is performed, and so on, and so on, and random injection is performed.

In Japanese Utility Model Application No. 64-36521, when the engine temperature is below a predetermined temperature, even if the oil pressure exceeds a predetermined value, the valve of the oil jet 10 does not open and remains closed. However, when the engine starts at a low temperature, the piston is cooled by the oil and the fuel is discharged unburnt, preventing the exhaust gas from turning into white smoke.

[Problem to be solved by the invention]

In the oil jet 1 shown in FIG. 3 described above, the steel balls 3 are pushed down randomly to inject oil, so that appropriate cooling oil is not injected depending on the operating condition of the engine.

Furthermore, the method disclosed in Japanese Utility Model Application Publication No. 64-36521 prevents the exhaust gas from turning into white smoke by preventing injection when the engine temperature is below a predetermined temperature.
Lubrication at low speeds is insufficient and the piston becomes scuffed.
uff, scratches) may occur.

In general, pistons are at high temperatures when the engine is under high load and revolutions, and must be cooled sufficiently.For this reason, conventionally, oil injection was targeted at the time when the piston was at its highest temperature, at top dead center. Also, at this time, there is a large amount of oil and the injection pressure is high, so effective cooling and lubrication are performed. However, in the case of low-speed rotation, the oil pressure is low and the injection timing of the oil jet is not particularly controlled, resulting in insufficient lubrication between the sliding surfaces of the piston and the bore, which may cause scuffing on the piston. .

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide means that can provide sufficient oil cooling at high speeds and, in particular, can inject oil at appropriate times and amounts at low speeds.

[Means to solve the problem]

In order to achieve the above object, the present invention includes an oil hole provided in a cylinder block of an engine, an oil jet pipe for injecting oil in the oil hole to the back surface of a piston of the engine, and an oil hole provided in the oil hole. In an oil cooling device for a piston, which is equipped with an oil jet valve between the cylinder block and the jet pipe, two oil passages are provided in parallel from the oil hole in the cylinder block to the oil jet valve, and one passage has an oil jet valve. To provide an oil cooling device for a piston, characterized in that a valve that is closed when the engine rotational speed is low is provided, and a valve that is opened when the rotating piston is located at the bottom dead center is provided in the other passage.

[For production]

When the engine is rotating at low speed, the valve in one of the two oil passages is closed, and the valve in the other passage opens when the piston is at the bottom dead center, so that oil is injected onto the back side of the piston. It will be done. During medium to high speed rotation, the valve in the one passage opens, and the valve in the other passage opens when the piston is at the bottom dead center, similar to when the piston is at low speed, and oil is injected onto the back surface of the piston.

〔Example〕

Examples will be described with reference to the drawings.

FIG. 1 shows a schematic diagram of a first embodiment of an oil cooling device (oil jet). In the figure, parts common to those in FIG. 3 are given the same reference numerals. 1 is an oil jet valve, 20 is an oil hole, 5 is a jet pipe,
10 is an oil jet, 16 is a cylinder block, and there are two oil passages 11 between the oil hole 20 in the cylinder block 16 and the oil jet valve 1.
．． 12 are arranged in parallel. One oil passage 11
is provided with a rotary valve 13, and the rotary valve 13
is connected to and driven by the engine crankshaft 35 via a gear (not shown). When the valve is at the bottom dead center, the valve is opened and the oil passage 11 is opened and the oil from the oil hole 20 flows into the jet valve l.
Injection is performed after Furthermore, a solenoid valve 14 is provided in the other oil passage 12, and this solenoid valve 14 is activated by an electronic control unit (ECU) based on input from an engine speed sensor.
40, it is closed only when the engine rotation speed is a predetermined low rotation speed, and is opened at other high and medium rotation speeds. Therefore, when the engine is rotating at high to medium speeds, the solenoid valve 14 is always open and the rotary valve 13 is open when the piston is at the bottom dead center, and when the engine is rotating at low speeds, only the rotary valve 11 is open when the piston is at the bottom dead center. There is.

Due to the above structure, when the engine rotates at medium and high speeds, the oil hole 20 and the oil jet valve 1 are replaced by the solenoid valve 1.
4 is always directly connected as in the conventional example shown in Figure 3, and in this case, because the rotation speed is high, a large amount of oil can be sent, the oil pressure is also high, and oil injection is performed strongly. and sufficient oil cooling is provided. Further, when the engine is rotating at low speed, the electromagnetic valve 14 is closed, and only the rotary valve 13 is opened only at the bottom dead center, and at low speed, the oil jet pipe 5 is located at the bottom dead center position closest to the piston. Reliable oil injection is performed on the back side. In this way, the injection timing is set only at the time when lubrication is most likely to occur, and oil is sufficiently supplied, thereby preventing injuries due to lack of lubricant such as piston scuffing at low speeds.

FIG. 2 shows a second embodiment. In this embodiment, the oil passage 1
1 is provided with a solenoid valve 15 in place of the rotary valve 13 of the first embodiment, and the other parts are the same as those in the first embodiment.
Since this is the same as the embodiment, detailed explanation will be omitted. The solenoid valve 15 is normally closed, but is controlled by the IECU 40 based on human power from the engine crank position sensor, and the solenoid valve 15 opens at the bottom dead center position of the piston to perform jet injection.

Therefore, since the solenoid valve 15 is used in place of the rotary valve 13, the cooling and lubrication effects of the oil on the piston 30 are generally the same as in the first embodiment, so a description thereof will be omitted.

〔Effect of the invention〕

By implementing the present invention, the following effects can be achieved.

(1) When the engine rotates at low speeds, oil is reliably injected at the bottom dead center position of the piston, thereby preventing damage such as scuffing that occurs on the pistons due to lack of lubricating oil at low speeds. Ru.

(2) By increasing the number of oil passages when the engine rotates at medium and high speeds, a large amount of oil can be injected, increasing the cooling and lubrication effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a piston oil cooling device according to the first embodiment, FIG. 2 is a schematic diagram of a piston oil cooling device according to the second embodiment, and FIG. 3 is a main part of a conventional piston oil cooling device. The sectional views are shown, and 31st ffl (a) shows the state when the oil jet valve is open, and (b) shows the state when the valve is closed. 1... Oil jet valve, 5... Oil jet pipe, 11. 12...Oil passage, 13...Rotary valve, 14. 15... Solenoid valve, 16...
・Cylinder block, 20...Oil hole, 30・
··piston. 1st Figure 40...Electronic control unit 葎1...珂3...冫4...; 10... 13Fig.

Claims (1)

[Claims] 1. An oil hole provided in the cylinder block of the engine, an oil jet pipe that injects the oil in the oil hole onto the back surface of the engine piston, and an oil hole provided between the oil hole and the jet pipe. In an oil cooling device for a piston equipped with a jet valve, two oil passages are provided in parallel from the oil hole in the cylinder block to the oil jet valve, and one passage is provided with an oil passage when the engine speed is low. 1. A piston oil cooling device comprising a valve that closes and a valve that opens when the rotating piston is at the bottom dead center in the other passage.