JPS5870020A - Piston cooling and controlling apparatus - Google Patents

Abstract

PURPOSE:To keep the temperature of a piston at optimum state, by providing a control valve for controlling the feeding amount of a cooling oil in a feeding passage for feeding the cooling oil to a piston thereby stopping the feeding of the cooling oil except when the heat load on the piston is high. CONSTITUTION:The cooling jet 3 for jetting cooling oil toward the cooling oil passage 2 of a piston 1 is connected with a cooling oil feeding passage 4, and a control valve 5 that is controlled to be opened or closed by a controller 6 is arranged in the cooling oil passage 4. The controller 6 is connected with a heat load detecting apparatus for detecting the suction air temperature 7, the engine rotational frequency 8, the load lever angle 9, the cooling oil temperature 10, the lubricant temperature 11, etc., so that according to the piston heat load, the control valve is actuated to control the feeding amount of the cooling oil 12. Accordingly, when the operation is such a state that the heat load is low at the time immediately after the starting, at the time of low or medium load, at the time of low or intermediate speed running, or the like, the control valve 5 is closed to keep the piston temperature at the optimum state. Thus the time required to attain the optimum value of the piston temperature can be reduced.

Description

Detailed Description of the Invention The present invention provides a control valve for controlling the supply amount of cooling oil in a cooling oil supply passage that supplies cooling oil for piston cooling of an internal combustion engine such as a diesel engine. The present invention relates to a piston cooling control device characterized in that the supply of cooling oil is stopped by a control valve only in a state of use other than under load.

Conventionally, this type of internal combustion engine piston cooling device is
Cooling oil is injected into the piston even when the piston is used in a range other than when all members are loaded, i.e. at low-medium loads and low-medium speeds. In general, when the maximum heat load and inertia force is applied to the piston, excessive interference occurs between the cylinder head and the valve, resulting in damage to the piston, etc. Under the above conditions, the gaps between the piston and the cylinder head, and between the piston and the valve, are almost zero, but under other usage conditions there are unnecessary gaps. As a result, this gap worsened combustion (see graph).

In addition, if the thermal load on the piston increases with engine performance improvements and durability cannot be ensured without piston cooling, cooling oil may be injected from the connecting rod end or a piston cooling jet may be installed. Cooling oil was injected and flowed onto the back side of the piston's combustion chamber to cool the piston. Furthermore, in order to achieve a strong cooling effect, piston cooling oil passages (cooling cavities) were provided to allow cooling oil to flow.

In these piston-cooled structures using cooling oil, the unnecessary gaps between the piston and cylinder head, and the gaps between the piston and the valve, as described above, further widen, which deteriorates performance at low and medium speeds, low and medium loads, fuel efficiency, and exhaust gas. It was working.

The purpose of the present invention is to eliminate the above-mentioned drawbacks.The purpose of the present invention is to detect the heat load on the piston, supply cooling oil to the piston only when the load is high, and perform cooling to properly maintain the top clearance. In order to do this, a control valve is installed in the cooling oil supply passage that supplies cooling oil to control the amount of cooling oil supplied.
Except when the heat load on the piston (which can be detected by the position of the injection pump lever, etc.) increases and cooling is required, that is, immediately after startup, at low-medium loads, at low-medium speeds, etc., the supply of cooling oil is stopped and the piston is cooled. It is an object of the present invention to provide a piston cooling control device characterized by maintaining temperature at an optimum state.

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The figure schematically shows a piston cooling control device according to the invention. In the piston cooling control device, cooling oil 12 is injected from a cooling jet 3 into a cooling oil passage 2 for a piston 1 used in an internal combustion engine. Cooling oil 12
The cooling oil is supplied from a cooling oil tank (not shown) to a cooling jet 3 through a cooling supply passage 4 by a pump (not shown). A control valve 5 is provided in the middle of the supply passage 4. The operation of the control valve 5 is controlled by a control device 6 with a built-in computer. This control device 6 controls the intake air temperature to 7. Ennon rotation speed 8. Load lever angle 9. It is connected to each heat load detection device such as cooling oil temperature 10, lubrication M (main hole) IF 1 degree 11, etc., and the control device 6 operates according to these factors to operate the control valve 5. ing.

Regarding operation, the piston heat load is generally low immediately after the internal combustion engine is started, under low to medium load, low to medium speed, etc. The piston cooling control device according to the present invention detects the piston thermal load from the above-mentioned factors, operates the control device 6 according to the measured value, operates the control valve 5, and controls the supply amount of the cooling oil 12. Normally, the control valve 5 is opened only when the load is high, and the cooling oil 12 is supplied to the cooling jet 2, from which it is injected against the piston 1. Thereby, the piston 1 can be cooled during high loads. The control valve 5 is closed at times other than high loads, that is, at low and medium loads including immediately after starting the internal combustion engine, and at low and medium speeds, cooling of the piston 1 by the cooling oil 12 is stopped rh, and the piston 1 immediately reaches the desired temperature. 3 Then, when the piston temperature rises and there is no need to heat the piston 1 any further, the control device 6 operates to operate and open the control valve 5 and direct the cooling oil 12 to the cooling jet 3. supply From there, the cooling oil 12 is injected into the cooling oil passage 2 of the piston 1, and the piston 1 is cooled. In this way, the temperature of the piston 1 is controlled by only a simple operation of the control valve 5, and the top clearance t between the piston head and the cylinder throat is maintained in an optimum state.

FIGS. 2 and 3 compare a piston cooling control device A using the piston cooling control device according to the present invention and a conventional device B.

In Figure 2, the horizontal axis is the engine rotation speed N (RPM),
The vertical axis is the piston temperature T ('C) of the piston ring groove.
, and shows the relationship in case of full load of Ennon.

Therefore, the diagonal line "i\t'" indicates the degree of performance improvement.

In Figure 3, the horizontal axis is the engine rotation speed N (RPM),
The vertical axis represents the axial average effective pressure P me (rei, 1), and shows the relationship when the engine is at full load. and,
A has a top clearance of 208, and B has a top clearance of t = 1. (1), and the shaded area indicates the degree of performance improvement.

As configured above, the piston cooling control device according to the present invention detects the piston thermal load and stops the supply of cold oil to the piston when the piston is in use except when the load is high.
In other words, it detects the piston's hot load and performs high-speed, high-angle (a
8. Maintain the piston temperature in 1 by appropriately cooling it by supplying cooling oil, and close the control valve at low to medium speeds and low to medium loads.
It is possible to stop the supply of cooling oil and promote the piston temperature to rise to the optimum value by -L, or to maintain it at the maximum temperature in each usage condition (below the limit temperature from performance and durability). The time it takes for the piston temperature to reach its optimum value is shorter than that of conventional models, and the piston can be expanded appropriately. By doing so, it is possible to improve output performance, fuel efficiency, exhaust gas, etc. Generally, when installing a piston cooling jet, 11 (lower main hole oil pressure at medium speeds becomes a problem, and in order to secure the required amount of oil) It will be necessary to adjust the oil pump capacity, but
Cold piston of the present invention! When using the Jl series control device, this becomes unnecessary.1. do. By keeping the engine temperature at an optimal state, poor combustion caused by low piston combustion chamber wall temperature can be improved regardless of the load or rotational speed. Furthermore, by reducing the bis[~n] amplitude,
The durability of the piston can be improved. In addition, when cooling the piston with cooling oil, the following ■~■ are used as countermeasures against high heat loads for the purpose of preventing overcooling at low-medium loads and low-medium speeds.In other words, ■cooling oil passage The most effective method is to cool a piston equipped with a piston with a piston cooling jet, and it is most effective for (1) cooling oil injection by a piston cooling jet and (2) cold 7JI curved injection of a light mountain at the end of a connecting rod.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a bison cooling control device according to the present invention, and FIGS. 2 and 3 are comparison diagrams between the present invention and a conventional one. DESCRIPTION OF SYMBOLS 1... Piston, 2... Cooling oil passage, 3... Piston cooling jet 1-14...' uI oil supply passage, 5... Control valve, 6... Control device, 12 ...
Cooling oil, t...Top clearance. Patent applicant: Hino Jidosha Kogyo Co., Ltd.

Claims (1)

[Claims] A control valve for controlling the supply amount of cooling oil is provided in the supply passage that supplies cooling oil to the piston, and this control valve is connected to a control device connected to a heat load detection device to detect the piston heat load. A piston cooling control device characterized in that a control valve stops the supply of cooling oil when the system is in use other than when the load is high.