JPS591043Y2 - Engine reverse rotation prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that automatically prevents reverse rotation of an engine such as a diesel or two-stroke engine that can rotate in reverse.

Japanese Utility Model Application Publication No. 50-13034, which is a prior art document of this type of reverse rotation prevention device, discloses that a pressure switch is provided in a suction pipe line with a check valve of a lubricating oil pump, and the pressure in the suction pipe is high when the reverse rotation is reversed. It is proposed to stop the engine by cutting off the fuel to the engine using a pressure switch, taking advantage of this phenomenon, but the suction pipe has abnormal pressure when the engine reverses. Since a relief valve must be provided to prevent the lubricating oil from rising, the structure becomes complicated and the installation space for the relief valve increases.Moreover, a pressure switch is installed in the suction line to the lubricating oil pump. However, it is difficult to apply this method to an engine in which the lubricating oil pump is built into the crankcase.

Therefore, in such a case, a pressure switch is installed in the lubricating oil passage leading from the oil filter connected to the discharge part of the lubricating oil pump to the lubricating parts such as the engine bearings, so that the pressure in the lubricating oil passage is reduced by the reverse rotation of the engine. When descending, a pressure switch is turned on to cut fuel to the engine and stop the engine.

However, in the lubricating oil system of an engine, a check valve is installed between the oil pump and the oil filter to prevent the lubricating oil in the oil filter from leaking to the oil pump side while the engine is stopped. The pressure in the lubricating oil passage where the pressure switch is attached does not suddenly drop when the engine rotates in reverse, but only gradually as lubricating oil leaks from lubricated parts such as bearings. There was a problem where this continued.

This invention cuts the fuel supply and stops the engine by taking advantage of the fact that the pressure in the lubricating oil passage from the lubricating oil discharge part to each lubricating part of the engine drops as the engine rotates in reverse. A bypass passage is provided for the oil filter with check valve material in the lubricating oil passage, and when the engine rotates in reverse, the lubricating oil in the lubricating oil passage is sucked back into the oil pump to hasten the pressure drop and shorten the engine. An example of this is explained with reference to a drawing. In the drawing, 1 is a diesel engine equipped with a fuel injection pump 2, and 3 is the engine 1.
A lubricating oil pump such as a gear or trochoid that is linked to the crankshaft or camshaft of the engine. The lubricating oil is supplied from the filter 6 through the lubricating oil passage 7 to various lubricating parts such as the bearings of the engine.

Reference numeral 8 denotes a pressure switch connected to the lubricating oil passage 7, and the pressure switch 8 is turned on when the pressure in the lubricating oil passage 7 drops below a set value, and the pressure switch 8 is turned on when the engine switch 9 is on. If so, the lever in the fuel injection pump 2 of the engine 1 is operated to the injection stop position via the relay 10 and the fuel control motor 11, and the oil filter 6 with the check valve 5 includes: A bypass passage 12 that directly communicates the discharge pipe 4 of the oil pump 3 and the lubricating oil passage 7 is provided, and a check valve 13 is provided in the bypass passage 12 that opens only in the direction from the lubricating oil passage 7 to the discharge pipe 4. It is made up of the following.

In this configuration, when the engine is rotating forward, lubricating oil is constantly sent to the lubricating oil passage 7 from the oil pump 3 via the check valve 5 and the oil filter 6, and since the pressure is high, the pressure switch 8 is turned off. However, engine 1 may not start for some reason (for example, when a car equipped with this engine starts reversing with the forward gear engaged while going uphill, or when the car starts moving backwards while going downhill). When the oil pump 3 rotates in the opposite direction (such as when starting to move forward with the lubricant inserted), the oil pump 3 that is linked to this will also rotate in the opposite direction, and the oil pump 3 will suck in lubricating oil from its discharge pipe 4. .

Then, the check valve 13 in the bypass passage 12 provided for the oil filter 6 with the check valve 5 opens from the lubricating oil passage 7 toward the discharge pipe 4, and the lubricating oil in the lubricating oil passage 7 becomes oily. Since it will be sucked back into the pump 3, the lubricating oil passage 1
The internal pressure drops rapidly, and when the pressure switch 8 is turned on, the lever inside the fuel injection pump 2 enters the fuel injection cut state, and the engine 1 is stopped.

As described above, this invention stops the engine by rapidly reducing the lubricating oil pressure by the reverse rotation of the oil pump accompanying the reverse rotation of the engine, so the time from the reverse rotation of the engine to the engine stop is shorter than the conventional one. , the drop in lubricating oil pressure can be reduced incomparably compared to systems that rely only on lubricating oil leaks, and the engine can be stopped almost at the same time as the engine rotates in reverse, improving safety. Since it is only necessary to provide a bypass passage with a check valve for the oil filter with a stop valve, the structure is not as complicated and the space required is small, and the pressure switch is connected to the discharge side of the lubricating oil pump. Since the lubricating oil pump is provided in the passage, it has the effect of being easily applicable to engines in which the lubricating oil pump is built into the crankcase.

[Brief explanation of drawings]

The drawings are diagrams showing embodiments of the present invention. 1... Engine, 3... Lubricating oil pump, 6... Oil filter, 5... Check valve, 7... Lubricating oil passage,
8... Pressure switch, 12... Bypass passage, 13
···non-return valve.

Claims (1)

[Scope of utility model registration request] The fuel supply to the engine is cut by detecting a pressure drop in the lubricating oil passageway from the oil filter with a check valve connected to the discharge pipe of the lubricating oil pump linked to the engine to the various lubricating parts of the engine. A bypass passage for an oil filter with a check valve is provided between the lubricating oil passage and the discharge pipe, and a check valve is provided in the bypass passage to open only in the direction from the lubricating oil passage to the discharge pipe. An engine reverse rotation prevention device equipped with a valve.