JP3473226B2 - Fuel transfer device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel transfer device, and more particularly to a fuel transfer device in which a fuel tank is composed of a main tank and a sub tank, and the fuel is transferred from the sub tank to the main tank via a pump. The present invention relates to a transfer device. 2. Description of the Related Art FIG. 2 shows an example of the configuration of an electric circuit of a conventionally known fuel transfer device, which is used, for example, in a mass-produced small bus. In FIG. 1, reference numeral 1 denotes a battery, which is connected to fixed contacts of a key switch 4 via fuses 2 and 3. When the key switch 4 is turned to an ON position,
The voltage of the battery 1 is supplied from the key switch 4 to the coil 7 a of the relay 7 via the fuse 5. When the coil 7a is excited, the normally open contact 7b of the relay 7 closes and the voltage of the battery 1 is
Coil 21 of relay 21 connected in parallel to each other through
a and the coil 22a of the relay 22. At this time, the coil 21a is connected in series to the normally open type fuel pump switch 8 and the liquid level switch 12 provided in the main fuel tank 11, and the coil 21a
Is excited when the operator (driver) manually operates the fuel pump switch 8 to turn it on and the liquid level switch 12 turns on. The liquid level switch 12 is turned off when the fuel level in the main fuel tank 11 is higher than the level indicated by the dotted line, and is turned on when the fuel level is lower than this level. Because
When the liquid level of the fuel in the main fuel tank 11 falls below the predetermined level indicated by the dotted line, the liquid level switch 12 is turned on to receive the fuel transfer from the sub fuel tank 13.
N. When the liquid level switch 12 is turned on,
Since both the coils 21a and 22a are excited, the normally-open contacts 21b and 22b respectively associated with them are closed. As a result, the coil 21a of the relay 21 is maintained in the excited state even when the operator releases the hand from the fuel pump switch 8, so that the relay 21 is held by itself. In the relay 22, the contact 22
Since b is closed, the coil 23a in the relay 23 is excited when the liquid level switch 14 provided in the auxiliary fuel tank 13 is turned on. The liquid level switch 14 in the sub-fuel tank 13 has just the opposite operation to that of the liquid level switch 12, and the fuel level of the sub-fuel tank 13 is higher than a predetermined level indicated by a dotted line. It turns on when the liquid level is high, and turns off when it is lower than this liquid level. Therefore, it is turned ON only when the fuel level in the sub fuel tank 13 is higher than the predetermined level, and the coil 23a of the relay 23 is excited. When the coil 23a is excited, the normally open contact 23b is closed, so that the fuel pump 15 is operated, and the suction force of the fuel pump 15 causes the pipe provided from the sub fuel tank 13 to the main fuel tank 11 to operate. Fuel will be transferred via 16. As described above, when the liquid level of the main fuel tank 11 is lowered, and when there is sufficient fuel in the sub fuel tank, the fuel is automatically replenished from the sub fuel tank to the main fuel tank. Become. In the drawings, reference numeral 17 denotes a fuel return pipe from the engine, 18 denotes a suction pipe for supplying fuel to the engine, and 19 denotes a sensor for measuring a fuel gauge (not shown). The operator presses the above-mentioned fuel pump switch 8 when the operator visually checks the fuel meter indicated by the measuring sensor 19 and judges that the fuel amount is running short (at any time). [0014] The electric circuit configuration of such a conventional fuel transfer device has the following problems. (1) Since four relays are used, the probability of occurrence of a failure increases in proportion to the number of relays used, and a plurality of relays are individually checked for repair in the event of an electrical failure. It takes time and effort, and the manpower and time required for repairs increase. (2) In order to secure a place and a space for installing four relays and their sockets, it takes time to design due to restrictions on installation environment space and restrictions such as easy inspection. (3) The cost increases proportionately due to the large number of relays used. Therefore, the present invention includes an electric circuit for transferring fuel from the sub fuel tank to the main fuel tank only when the fuel amount in the sub fuel tank is equal to or more than a predetermined value and the fuel amount in the main fuel tank is equal to or less than the predetermined value. An object of the present invention is to improve the reliability of a fuel transfer device by reducing the number of relays used as much as possible to reduce the possibility of occurrence of a failure. In order to achieve the above object, a fuel transfer device according to the present invention provides a fuel transfer device in which a fuel amount of a main fuel tank having a fuel supply pipe and a fuel return pipe to an engine has a predetermined value. When the fuel level of the sub fuel tank is detected by the main liquid level switch, and when the sub fuel level switch detects that the fuel amount in the sub fuel tank is equal to or more than a predetermined value, the main fuel tank is separated from the sub fuel tank by the fuel pump. A first relay that is excited when a key switch is turned on, a normally open contact of the first relay, a normally open type fuel pump switch, and the main liquid level switch. A second relay having a coil forming a series circuit, and a series circuit formed by being connected to a normally open contact of the second relay forms a parallel circuit with the fuel pump switch; Backflow prevention means for self-holding the second relay;
Wherein the fuel pump is connected in series to the normally open contact of the second relay, and the main liquid level switch is connected in series with the sub liquid level switch. That is, in the present invention, the key switch is
N operation, the first relay is energized, and the first relay
When the fuel pump switch is manually operated at this time, the coil of the second relay is connected to the main liquid level switch of the main fuel tank and the main liquid level switch. Excitation is performed on condition that both the sub liquid level switches in the sub fuel tank connected in series with the surface level switch are turned on. When the liquid level of the fuel in the main fuel tank is equal to or higher than a predetermined value, it is not necessary to supply the fuel to the main fuel tank. Second regardless of the state of
Relay coil is not energized. On the other hand, when the liquid level of the fuel in the main fuel tank is lower than a predetermined value, the main liquid tank needs to be replenished with fuel, so that the main liquid level switch is turned on. When the liquid level of the fuel is lower than a predetermined value and the sub liquid level switch is OFF, the coil of the second relay is not excited, but the fuel level of the sub fuel tank can be replenished at the predetermined value or more. When the fuel level is sufficient and the sub liquid level switch is ON, the coil of the second relay is excited. When the coil of the second relay is energized, the normally open contact closes. The normally open contact is connected in series with the backflow prevention means, and the series circuit is connected in parallel with the fuel pump switch. Therefore, even if the fuel pump switch is released, the excited state of the second relay is maintained by itself. Since the contact of the second relay is connected in series to the fuel pump, the fuel pump is connected to the first and second relays.
Is driven by the voltage applied from the contact point of the relay, so that fuel is supplied from the auxiliary fuel tank to the main fuel tank. As described above, in the present invention, fuel transfer is realized by two relays. FIG. 1 shows an example of an electric circuit configuration of a fuel transfer device according to the present invention. In this embodiment, FIG.
3 in that the number of relays is reduced from four to two as compared with the conventional example shown in FIG. That is, the relay 7 as the first relay
The contact 7b is connected to a normally open type fuel pump switch 8 and a contact 9b of a relay 9 as a second relay. The fuel pump switch 8 further includes a coil 9a of the relay 9 and a diode 10 as a backflow prevention means. Connected to the cathode. The coil 9a of the relay 9 is connected to the main fuel tank 11
The anode of the diode 10 is connected to the contact 9 b of the relay 9 and the fuel pump 15. The liquid level switch 12 is connected in series with the (sub) liquid level switch 14 in the sub fuel tank 13 and is connected to the ground potential. The above point is different, and the other configuration is the same as the conventional example of FIG. In the operation of such an embodiment, FIG.
By turning the key switch 4 to the ON position in the same manner as in the conventional example, the coil 7a of the relay 7 is excited and the normally open contact 7
b will be closed. At this time, the operator operates the measurement sensor 19
If it is determined that the fuel amount is insufficient by looking at the fuel gauge indicated by the operator and the fuel pump switch 8 is pressed,
The voltage of the battery 1 is applied to the coil 9a of the relay 9 via the contact 7b and the fuel pump switch 8, but at this time, as described above, the fuel amount in the main fuel tank 11 becomes smaller than the predetermined position indicated by the dotted line. The liquid level switch 12 is turned on when the fuel is supplied, and the liquid level switch 14 is also turned on when the fuel level in the auxiliary fuel tank 13 is larger than the predetermined position indicated by the dotted line and there is a margin for the replenishable fuel amount. Therefore, only under such conditions, the coil 9a of the relay 9 is excited. When the coil 9a is excited, the contact 9b is closed, and the voltage of the battery 1 is changed to the contacts 7b, 9b.
And relay 9 is applied to coil 9a via diode 10, so that relay 9 is self-held even when fuel pump switch 8 is released. The voltage of the battery 1 applied to the anode of the diode 10 is also applied to the fuel pump 15. The fuel pump 15 is driven in the same manner as in the prior art shown in FIG. The fuel at 13 is transferred to the main fuel tank 11 via the pipe 16. As described above, according to the fuel transfer device of the present invention, the amount of fuel in the main fuel tank having a fuel supply pipe and a fuel return pipe to the engine is reduced to a predetermined value or less. If the normally open fuel pump switch is manually operated when the sub-liquid level switch detects that the fuel amount in the sub-fuel tank is equal to or more than a predetermined value, the state is changed to the second state. Since the fuel is held by the first and second relays and the fuel pump is driven to transfer the fuel from the sub fuel tank to the main fuel tank, the two relays are used while maintaining the same function as the conventional example. As a result, the failure rate at which the fuel pump cannot be operated can be reduced, so that the reliability is improved. Further, it is easy to secure a place and a space for installing the relay, and the manpower in the design is gradually reduced, and the cost is also reduced in proportion thereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an example of an electric circuit configuration of a fuel transfer device according to the present invention. FIG. 2 is a block diagram showing an example of an electric circuit configuration of a conventional fuel transfer device. [Description of Signs] 1 Battery 4 Key switch 7 First relay 8 Fuel pump switch 9 Second relay 10 Diode 11 Main fuel tank 12, 14 Liquid level switch 13 Secondary fuel tank 15 Fuel pump 16 In the transfer piping diagram, The same reference numerals indicate the same or corresponding parts.

Continuation of the front page (56) References Japanese Utility Model Sho 57-141119 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 37/00 301 B60K 15/03 B60R 16/02 645

Claims (1)

(57) [Claim 1] A main liquid level switch detects that a fuel amount of a main fuel tank having a fuel supply pipe and a fuel return pipe to an engine has fallen below a predetermined value, and In the device for transferring fuel from the sub fuel tank to the main fuel tank by the fuel pump when it is detected by the sub liquid level switch that the fuel amount of the sub fuel tank is equal to or more than a predetermined value, the key switch is turned on. A second relay having a coil that forms a series circuit with a first relay that is energized, a normally open contact of the first relay, a normally open fuel pump switch, and the main liquid level switch; A series circuit formed by being connected to the normally open contact of the second relay, forming a parallel circuit with the fuel pump switch, and comprising a backflow preventing means for self-holding the second relay; Wherein the fuel pump is connected in series to a normally open contact of the relay, and the main liquid level switch is connected in series with the sub liquid level switch.