JPH01138332A - Device for preventing reverse revolution of engine - Google Patents

Abstract

PURPOSE:To prevent an engine from being reversely revolved quickly and positively, and thereby improve safety by detecting that the engine is being reversely revolved, and thereby letting the output of said detection interrupt fuel supply to the engine. CONSTITUTION:When a key switch 2 is connected to a starting contact point 4, a relay 6 is excited so as to let a starter 5 be actuated. In addition, respective relays 21 and 20 are excited so as to let current flow to a motor 8 for letting the opening/closing lever 13 of a fuel injection pump 12 be swung from a closing position B to an opening position A. And then, when an engine is reversely rotated, a lubricating pump is reversely rotated so as to let an oil switch 17 be turned on. After then, a relay 19 is excited, concurrently the relay 21 is demagnetized. In addition, the relay 20 is excited via a switch 16 so as to allow the motor 8 to return the opening/closing lever 13 from the opening position A to the closing position B. Following which, the switch 16 is turned off so as to let the relay 20 be de-magnetized for letting the motor 8 come to a stop. As a result, fuel feed is suspended, thereby letting the engine be suspended in operation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a reverse rotation prevention device for an engine.

(Prior Art and Problems) Vehicles such as agricultural tractors are equipped with diesel engines and run using this as a power source.

Conventional diesel engines did not have any measures in place to prevent reverse rotation, so if the engine unexpectedly stops and you begin to reverse while driving, an external force may cause the engine to reverse, which is extremely dangerous. Ta.

In view of these conventional problems, it is an object of the present invention to immediately detect and stop the engine when it starts to reverse.

(Means for Solving the Problems) To achieve this, the present invention provides a detection means 17.33 for detecting reverse rotation of the engine;
The engine is equipped with fuel cutoff means 8 and 12 for cutting off the supply of fuel to the engine based on the output of the engine.

(Operation) When the engine reverses, the detection means 17.33 detects this and the fuel cutoff means 8.13 cuts off the supply of fuel to the engine. Therefore, the engine then stops reversing.

(Example) Hereinafter, the present invention will be described in detail with reference to the illustrated example.
In the figure, 1 is a power supply, 2 is a key switch, and has an on contact 3 and a start contact 4. 5 is the diesel engine starter, 6 is the starter relay, and starting safety switch 7
It is connected to the starting contact 4 of the key isochi 2 via. A contact 6a of starter relay 6 is connected to starter 5.

Reference numeral 8 denotes a motor for opening and closing the fuel system of the engine, and as shown in FIG. When the opening/closing lever 13 is in the open position A, fuel can be injected from the injection nozzle 14, and when it is in the closed position B, the fuel supply is cut off. The motor 8 has an opening/closing lever 13
is open and closed position A.

Switches 15, 16 are provided to detect the presence in B.

An oil switch 17 is provided in the engine's lubrication system and is configured to be turned on when a lubrication pump directly connected to the engine is stopped or reversed. 18 is a lamp, and 19 is a relay, which has an a contact 19a and a b contact 19b. A relay 20 has an a contact 20a and a b contact 20b. 21 is a relay, with an a contact 21a and a b contact 21
It has b. 22 is a timer circuit, transistor 2
3.24, a diode 25.26, a constant voltage diode 27.2B, a capacitor 29.30, and other resistors. 31 is a timer circuit 22
This output relay has an a contact 31b. 32 is a diode.

Note that the oil switch 17 constitutes a detection means, and the motor 8, fuel injection pump 12, etc. constitute a fuel cutoff means.

Next, the operation will be explained with reference to FIG. When the key switch 2 is connected to the on contact 3, the oil switch 17 is in the on state, so the lamp 18 lights up and the relay 19 is energized, its a contact 19°8 turns on and its b contact 19b turns off. A relay 21 is connected to the starting contact 4 side of the key switch 2.

When the key switch 2 is connected to the starting contact 4, the relay 6 is energized and its a contact 6a is turned on, so that the starter 5 begins to operate. In addition, the relay 21 is excited via the diode 32 and the a contact 19a, and the a contact 21a is turned on.
Since the b contact 21b is turned off, the relay '-20 is energized,
The a contact 20a is turned on. Therefore, current flows to the motor 8 via the a contact 20a, and the motor 8 operates to swing the opening/closing lever 13 of the fuel injection pump 12 from the closed position B to the open position. Then, in the middle of this, the switch 16 is turned on, and when the open/close lever 13 reaches the open position A, the switch 15 is turned off, so the relay 20 is demagnetized, the A contact 20a returns to OFF, and the B contact 20b returns to ON. Therefore, the motor 8 stops. Since the starter 5 is operating at this time, the fuel injection pump 12 operates and injects fuel from the injection nozzle 14, thereby starting the diesel engine.

On the other hand, when the key switch 2 is connected to the starting contact 4, the capacitor 29 is charged at that moment and the transistor 23 is turned on. This will not turn on because the potential will rise. Therefore, transistor 24 remains off.

After starting the engine, when the key switch 2 is returned from the starting contact 4 to the ON contact 3, the constant voltage diode 27 is turned on and current flows through the transistor 23, so the transistor 24 is turned on and the relay 31 is energized. Its a contact 31
The relay 21 is energized from b. This continues for a time T until capacitor 29 discharges. That is, when the engine starts, the oil switch 17 is turned off, the relay 19 is demagnetized, and the relay 21 is kept in an excited state via its b contact 19b, but there is a delay time of several seconds before the oil switch 19 is turned off. During this time, the timer circuit 22 is activated to supply electricity through the a contact 31a of the relay 31 to keep the relay 21 in an excited state.

If the engine starts to rotate in reverse for some reason while the engine is running, the lubricating pump rotates in reverse, and the oil switch 17 is turned on with a slight delay from the occurrence of the reverse rotation. Then, the relay 19 is energized and its b contact 19b is turned off, so the relay 21 is demagnetized, the a contact 21a is turned off, and the b contact 21b is turned on. Then, the relay 20 is excited via the B contact 21b and the switch 16, and the A contact 20a is turned on, so the motor 8 is operated and the opening/closing lever 13 is moved from the open position A to the closed position B.
Go back to. When the opening/closing lever 13 reaches the closed position B, the switch 16 is turned off, the relay 20 is demagnetized, and the a contact 20a is turned off, so that the motor 8 is stopped.

When the opening/closing lever 13 returns to the closed position B in this way, the supply of fuel from the fuel injection pump 12 is cut off.
The engine will then immediately stop, preventing further reversal.

In addition, in the embodiment, the oil switch 17 is used as the detection means.
However, a pressure switch provided for checking the air cleaner may be used, and detection may be made by turning on the pressure switch when a reverse rotation of the engine occurs.

Alternatively, a regulator charging circuit 33 may be used as shown in FIG. That is, since there is a transient stop state when the engine reverses, the regulator charging circuit 33 whose voltage decreases during the stop may be used to determine the occurrence of reverse.

Of course, it is also possible to use other means than these.
It is not limited to the examples.

The fuel cutoff means may be a solenoid valve or the like.

(Effects of the Invention) According to the present invention, the means 17°33 for detecting the reverse rotation of the engine
, and the fuel cutoff means 8.13 cuts off the supply of fuel to the engine based on the output thereof, so that the engine immediately stops thereafter.

Therefore, the reversed state does not continue as in the conventional case, and safety is significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a configuration diagram of the fuel cutoff means, Fig. 3 is a time chart of the same, and Fig. 4 is a circuit diagram showing an embodiment of the present invention.
The figure is a circuit diagram showing another embodiment. 2... Key switch, 8... Motor, 12... Fuel injection pump, 17... Oil switch, 19, 20
．． 21.31...Relay, 22...Timer circuit. Patent applicant: Kubota Iron Works Co., Ltd. (Fig. 3 a, C3vL) Fig. 4

Claims (1)

[Claims] (1) An engine characterized by comprising detection means 17, 33 for detecting reverse rotation of the engine, and fuel cutoff means 8, 12 for cutting off the supply of fuel to the engine based on the output of the detection means 17, 33. anti-reverse device.