JPS62110444A - Electric source circuit for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a power supply circuit for a vehicle such as a diesel vehicle.

(Prior Art) In vehicles such as diesel cars, when starting the engine, a 24V starter motor is driven to obtain a large starting torque in order to improve starting characteristics.

For this purpose, the normal electrical load is also set to 24V specification, or a 24V-12V voltage transformer is prepared to supply power to the 12V specification electrical load (Japanese Patent Laid-Open No. 55-7113
No. 8〉. Figure 2 is an example of such a conventional 24V engine starting circuit using a 24V specification electrical load, with 1 and 2 being a 12V battery, 3 being a 24V alternator,
4 is an ignition switch, ACC is an accessory contact, IGN is an ignition contact, and 5TART is a start contact. 5 is a 24V starter motor connected to the start contact of ignition switch 4, 6a
, 6b are switches SWl.

A 24V specification electrical load is activated by turning on SW2, a 24V lamp 7 is turned on by turning on lamp switch SW3, and fuses Fl and F2.

Turn ignition switch 4 to 5TAR when starting the engine.
When turned to the T contact, 12V batteries 1 and 2 are connected in series to supply 24V to the starter motor 5 to obtain the desired starting torque, and then connected to the ACC and IGN contacts to connect the accessory load (not shown). ) and electrical load 6a,
6b, 24V is supplied to the 24V lamp 7.

However, 24V specification electrical units are used in small quantities, resulting in high costs, and 24V-12V voltage converters are large and expensive, which is disadvantageous in terms of economy.

(Objects and Structure of the Invention) The present invention has been made in view of the above points, and improves engine startability without using a voltage converter.
The purpose is to enable the use of 2V electrical loads,
To achieve this purpose, two 12V batteries are used; when the ignition switch is turned to the starter contact, the two 12V batteries are connected in series to obtain 24V; otherwise, the two 12V batteries are connected in parallel. It was configured to obtain 12V by connecting it to.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a circuit diagram of one embodiment of a power supply circuit according to the present invention, and the same reference numerals as in FIG. 2 indicate the same components.

In the figure, 3' is a 12V alternator, 8 and 9 are relays connected to the negative and positive terminals of battery 1, respectively, and excitation relays 8a and 8b, respectively.
, a normally open contact No. and a normally closed contact No. A relay 10 is connected to the positive terminal of the battery 2, and this relay 1
0 also has an excitation coil 10a, a normally open contact No., and a normally closed contact NG, and the normally open contact No. of the relay 10 and the normally open contact No. of the relay 8 are electrically connected. As an electrical load,
Switch SW1. 12 activated by turning on SW2
This is a 12V lamp 12 that is activated by a V specification electrical load and turning on the lamp switch SW2. Note that the terminal a of the ignition switch 4 is connected to the positive terminal of the battery 2.

Now, when the ignition switch 4 is connected to the starter contact when starting the engine, current flows from the battery 2 through the terminal a and the starter contact to the excitation coil 3a of the relay 8, the excitation coil 9a of the relay 9, and the excitation coil 10a of the relay 10. , the contact of each relay switches from normally closed contact NC to normally open contact No. As a result, battery 1 and battery 2 are connected in series, and starter motor 5 receives 24V.
voltage is applied.

On the other hand, since the normally closed contacts NC of each relay are closed except when the engine is started, batteries 1 and 2 are connected in parallel, and the electrical load 11a is connected.

A voltage of 12V is applied to the 11b1 lamp 12.

In this way, when starting the engine, a voltage of 24V is applied only to the starter motor 5, and at other times, a voltage of 12V is applied to the electrical load.

Further, since the batteries 1 and 2 are equally charged by the 12V alternator 3', there is no imbalance in capacity.

Although a large current (for example, 20 OA or more) flows through the relay used in the above embodiment, an extremely large relay already used in electric winches and the like can be used.

(Effects of the Invention) As explained above, in the present invention, two 12V batteries are used, and when the ignition switch is turned to the start contact, the two 12V batteries are connected in series to obtain 24V, and otherwise Now, since we configured the system to connect two 12V batteries in parallel to obtain 12V, it is possible to drive a 24V starter motor when starting the engine in vehicles such as diesel cars, improving starting performance. Normally, 12V can be supplied to the electrical load, so it is possible to use a 12V specification electrical load, which is advantageous in terms of cost. Further, a 24V-12V voltage converter is not required, which is also economically advantageous.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of a vehicle power supply circuit according to the present invention, and FIG. 2 shows an example of a conventional vehicle power supply circuit.

Claims (1)

[Claims] Two 12V batteries, and a switching means that connects the two 12V batteries in series when the ignition switch is turned to the starter position, and connects the two 12V batteries in parallel when the ignition switch is in a position other than the starter position. Vehicle power supply circuit with