JPS606015A - Piston cooling system - Google Patents

Abstract

PURPOSE:To prevent abnormal reduction of hydraulic pressure for ensuring sufficient supply of oil to other lubricating parts than pistons by providing cut-off valves in oil galleries for cooling pistons which are operative in response to negative pressure in an intake system and performing oil injection toward the pistons only when required. CONSTITUTION:A cylinder block 1 has oil galleries 2 for conveying oil under pressure from a oil pump. Each of the oil galleries 2 has a connecting passage extending in association with each of cylinders 3. Each of the connecting passages 4 is connected to a jet pipe 6 adapted for injecting oil toward the backside of a piston 5. There are provided in each oil gallery 2 cut-off valves 7 each of which comprises a cylindrical member having an outer diameter approximately equal to the inner diameter of the oil gallery 2 and located at a position corresponding to each connecting passage 4, and the cut-off valves 7 are connected in a unit to a connecting rod 9 which is coupled to a diaphragm 10 into which negative pressure is introduced. Thus, under low load where the negative pressure is high, the cut-off valves 7 cut off the connecting passages 4 to stop oil injection toward the pistons 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston cooling device for an internal combustion engine for an automobile, and more particularly to a type of piston cooling device in which oil is injected from a diene pipe toward the back surface of the piston.

Conventionally, an oil jet pipe is installed directly under the oil gear rally installed in the cylinder block, and oil is sprayed onto the back surface of the piston to prevent thermal deformation of the piston or lower the piston surface temperature, thereby improving knocking under high loads. Attempts are being made. However, when an oil pipe is provided in a normal engine, many mountains of oil are injected from the oil jet pipe, which may cause the oil pressure in the hydraulic pressure transmission system to drop and the oil to be insufficiently distributed to other parts. In particular, when the engine speed is low, the oil pump speed is also low, so the oil pressure is lowered more than necessary due to oil injection from the oil jet pipe, which may make it impossible for lash adjusters to operate smoothly or prevent rotating parts from operating smoothly. There was a risk that lubrication would be lost and seizure would occur. Furthermore, since oil is constantly injected while the engine is operating, the oil becomes hot and loses viscosity due to the effects of oxidation and the like, resulting in severe deterioration of the oil.

The present invention is directed to a piston cooling device of the type that injects oil from a jet pipe toward the back surface of the piston, in order to suppress oil deterioration by preventing an excessive drop in the oil pressure of an oil pumping system and an increase in the temperature of the oil. With the goal.

In order to achieve this objective, in the piston cooling device of the present invention, communication passages are cut off in the oil gear rally provided in the cylinder block in correspondence with each communication passage that communicates with the oil gear rally and communicates with the jet pipe. A shutoff valve is provided having an oil passage that allows oil to flow within the oil gear gallery, each shutoff valve being connected together by a connecting rod, and one end of the connecting rod being actuated by the negative pressure of the intake system. connected to the diaphragm.

In such a piston cooling system, the operation of the diaphragm 17 controls the shutoff and conduction of the communication passage by the shutoff valve via the connecting rod, and when the engine is under light load, the communication passage is shut off and oil injection is stopped. When the load is high, the communication path is made conductive and oil is injected from the piston 1 to the back surface of the piston. Therefore, oil is injected only when the piston needs to be cooled under high loads, thereby preventing overcooling of the piston and reducing oil pressure during light loads.

In addition, if the diaphragm is controlled based on the engine speed, injection can be stopped especially when the engine speed is low and the oil pressure is low, preventing the oil pressure from dropping more than necessary, and improving the operation and lubrication of each part of the engine. Necessary oil pressure and oil volume are ensured. Furthermore, since the oil is not constantly injected during engine operation, the temperature of the oil is suppressed and deterioration is suppressed, the lubricating performance and other properties of the oil are stably maintained, and the life of the oil is extended.

Preferred embodiments of the piston cooling device of the present invention will be described below with reference to the drawings.

1 to 3 show a piston cooling device according to a first embodiment of the present invention. In the figure, 1 is a cylinder block, and the cylinder block 1 is provided with an oil gear rally 2 that guides oil pumped from an oil pump (not shown). Oil gear 2 has 3 cylinders for each cylinder.
Communication passages 4 are connected in correspondence with each other, and a jet vibro that injects oil toward the back surface of the piston 5 is connected to each communication passage 4.

A cutoff valve 7 is provided in the oil gear gallery 2 at a position corresponding to each communication path 4 . The cutoff valve 7 is made of a cylindrical member having an outer diameter that is approximately the same as the inner diameter of the oil gear gallery 2, and is able to cut off communication between the communication passage 4 and the oil gear gallery 2 if it is located directly above the communication passage 4. The shutoff valve 7 is provided with an appropriate number of oil passages 8 that communicate with each other before and after the shutoff valve 7 in order to allow oil to flow within the oil gear gallery 2.

Each shutoff valve 7 is integrally connected by a connecting rod 9, and by moving the connecting rod 9 in the axial direction, each shutoff valve 7
are moved at the same time. The interval between each shutoff valve 7 is adjusted to the interval between each communication passage 4. Therefore, when the cutoff valve 7 is located directly above the communication passage 4, communication between all the communication passages 4 and the oil gear rally 2 is cut off, and when the cutoff valve 7 is located away from the communication passage 4, communication between all the communication passages 4 and the oil gear rally 2 is cut off. 2 are electrically connected.

A diaphragm 10 is provided at one end of the connecting rod 9, and the connecting rod 9 is connected to the diaphragm 10. A negative pressure circuit of the intake system, which will be described later, is connected to the diaphragm chamber of this diaphragm 10, and the diaphragm 10 pulls the connecting rod 9 when negative pressure is introduced, and sets the diaphragm blank when no negative pressure is introduced. The connecting rod 9 is actuated by a pulled spring (not shown) in the direction of pushing the connecting rod 9.

FIG. 4 shows an embodiment of the intake-end negative detour that controls the operation of the diaphragm 10. A negative pressure circuit 11 is connected to the diaphragm 10 and communicated with an intake system (not shown). The negative pressure circuit 11 includes a vacuum switching valve 12 as a switching valve. is incorporated. Vacuum sui・
A bypass circuit 13 and a direct circuit 14 from the intake system are connected to the switching valve 12, and the bypass circuit 13 includes a check valve 15 and a reserve tank 16 for storing negative pressure in order from the intake system side. ing. The vacuum switching valve 12 connects the circuit 14 and the negative pressure circuit 17 to the diaphragm 10 when activated, and connects the bypass circuit 13 and the negative pressure circuit 17 when activated.
It is switched so that conduction is established between the two.

The vacuum switching valve 12 is connected to the electronic control device 1
8 and is operated by an on/off signal 19 from an electronic control unit 18. A signal 20 indicating the engine speed is input to the electronic control devices 1 and 8, and the electronic control device 18 turns on the vacuum switching valve 12 when the engine speed reaches a certain speed N1 or higher. controlled to emit a signal.

This constant rotational speed N1 is desirably a rotational speed slightly higher than the normal idle rotational speed, for example, about 700 rpm.

The operation of the piston cooling device configured as described above will be described below.

The movement of each shutoff valve 7 is controlled simultaneously by a diaphragm 10 via a connecting rod 9. Then, when negative pressure is introduced into the diaphragm 10, the connecting rod 9 is pulled and each shutoff valve 7 is positioned directly above the communication path 4 to shut off the communication path 4, and the injection of oil from the jet vibro is stopped. Ru.

When negative pressure is not introduced into the diaphragm 10, the connecting rod 9 is pushed back, each cutoff valve 7 is removed from the position of the communication path 4, the communication path 4 and the oil gear rally 2 are brought into communication, and oil is injected from the jet vibro. Regardless of the control of the position of the shutoff valve 7, the flow of oil within the oil gear gallery 2 is ensured by the oil passage 8 provided in the shutoff valve 7.

The position of the shutoff valve 7 is controlled by a diaphragm 10 actuated by negative pressure in the intake system. In the normal operating range where the engine speed is above a certain speed N1,
Since the vacuum switching valve 12 is turned on by the Φ signal 19 from the electronic control device 18, the diaphragm 1
0, the negative pressure of the intake system is directly introduced. When the engine is under light load, the negative pressure in the intake system becomes large, so the negative pressure acts on the diaphragm 10 and pulls the connecting rod 9, causing the connecting passage 4
is shut off and oil injection from the jet vibro is stopped. When the load is light, the thermal load applied to the piston is small and there is little effect on engine performance due to thermal deformation of the piston, so there is no need for cooling by oil injection.

Particularly when the engine speed is low, the oil pressure sent from the oil pump is low, but by stopping oil injection, the oil pressure is prevented from dropping more than necessary, and sufficient oil pressure and oil volume are supplied to other parts of the engine. Secured. Moreover, by stopping unnecessary oil injection, the temperature increase of the oil is suppressed and deterioration is suppressed accordingly.

On the other hand, when the engine is under high load, the negative pressure in the intake system becomes small and approaches atmospheric pressure, so the spring in the diaphragm 10 pushes back the connecting rod 9, making the communication path 4 conductive and allowing oil to flow from the jet vibro. 'fi4III will be done. The piston is sufficiently cooled by the oil injection, and the original piston cooling function is performed to suppress knocking and prevent thermal deformation.

Further, when the engine speed is below N1, that is, when the engine is idling or at a low speed close to that, the vacuum switching valve 12 is turned off by the signal 19 from the electronic control device 18, and the die 17 flamm 10 and the reserve Tank 16 is made conductive. Since negative pressure is stored in the reserve tank 16, the diaphragm 10 is actuated by this negative pressure, the communication path 4 is cut off, and oil injection is stopped. As a result, hydraulic injection is not performed when the engine speed is low and the oil pressure is low, such as when idling, preventing an abnormal drop in the oil pressure, ensuring oil pressure and cuffs to other engine parts, and causing problems such as seizure. occurrence is prevented. Furthermore, deterioration of oil due to unnecessary oil injection at low rotational speeds is also suppressed.

Next, FIG. 5 shows a piston cooling device according to a second embodiment of the present invention. In this embodiment, the shutoff valve 21 is ~
It consists of a pair of fan-shaped members, and between the fan-shaped members is an oil passage groove 22 that serves as an oil passage for ensuring the flow of oil into the oil gear gallery 2. Each of the shutoff valves 21 is integrally connected by a connecting rod 23, and one end of the connecting rod 23 is connected to the diaphragm 10 via a link mechanism 24. In such a device, the connecting rod 23,
The cutoff valve 21 is rotated within the oil gear rally 2 and the communication path 4 is opened.
When the cutoff valve 21 comes directly above the communication path 4, the communication path 4 is cut off.
The oil passage groove 22 is now electrically connected. Other configurations,
The operation is similar to the first embodiment.

As explained above, when using the piston cooling device of the present invention, a shutoff valve is provided in the oil gear gallery, and a diaphragm that operates using negative pressure in the intake system can control shutoff and conduction of oil to the jet pipe. This makes it possible to stop oil injection when there is no need for oil injection when the engine is under light load, or when the engine speed is low and the oil pressure is low, preventing abnormal oil pressure drops and ensuring that other lubricating parts have sufficient oil injection. It is possible to ensure a sufficient oil pressure and oil amount, and by injecting oil only when necessary, it is possible to prevent the oil from increasing in temperature and suppress deterioration.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a piston cooling device according to a first embodiment of the present invention, Fig. 2 is a partial cross-sectional view of the device shown in Fig. 1 along line ■-■, and Fig. 3 is a perspective view of the area around the shutoff valve. 4 is a system diagram of a negative pressure circuit, and FIG. 5 is a partial perspective view of a piston cooling device according to a second embodiment of the present invention. 1... Cylinder block 2... Oil gear rally 4... Communication passage 5,... Piston 6... Jet pipe 7.21... ...Shutoff valve 8...Oil passage 9.23...Connecting rod 10...Tie\7 flamm 11...Negative pressure circuit 12... ... Vacuum switching valve 13 as a switching valve ... Bypass circuit 14 ... Circuit from the intake system 16 ... Reserve tank 17 ... Negative to the diaphragm Pressure circuit 18...
...Electronic control & II device 20...Engine speed signal Fig. 3 Fig. 41 U Fig. 5

Claims (3)

[Claims] (1) In a piston cooling device that injects oil from a jet pipe toward a piston surface through a communication passage communicating with the oil gear, which is force-fed through an oil gear rally provided in a cylinder block, each of the communication passages is provided in the oil gear Correspondingly, a shutoff valve is provided which has an oil passage that can shut off the communicating passage and allows oil to flow within the oil gear gallery, and each shutoff valve is connected together via a connecting rod, and one end of the connecting rod A piston cooling device characterized in that the piston cooling device is connected to a tire flam that is operated by negative pressure in an intake system. (2) A negative pressure circuit of an intake system is connected to the diaphragm so that when negative pressure is introduced into the diaphragm, the cutoff valve operates in a direction to shut off the communication passage, and the negative pressure circuit is connected to the negative pressure circuit. The piston cooling device according to claim 1, which incorporates a switching valve that switches between a circuit from an intake system and a circuit from a reserve tank that stores negative pressure. (3) The switching valve is controlled so as to switch the circuit from the intake system when the engine speed is high and to the circuit from the reserve tank when the engine speed is low. Piston cooling device.