US3594029A

US3594029A - Control circuit for a starter solenoid on a vehicle

Info

Publication number: US3594029A
Application number: US28316A
Authority: US
Inventors: William David Holt
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-05-27
Filing date: 1970-04-14
Publication date: 1971-07-20
Anticipated expiration: 1988-07-20
Also published as: DE2024441A1; GB1296838A; ES380000A1; FR2048851A5

Abstract

A control circuit for a vehicle starter solenoid which operates so that a second attempt to start an engine cannot be made until a predetermined time has elapsed after a first attempt to start the engine. A starter switch energizes a first rely which completes a circuit to the starter solenoid, completes a selfhold circuit to itself and charges a capacitor connected across the base emitter path of a transistor. The transistor then energizes a second relay which opens a contact between the starter switch and the first relay to break the circuit to the first relay other than through the self-hold circuit. The first relay is then deenergized when the starter switch is opened so that the capacitor discharges through the base-emitter path of the transistor to keep the second relay energized for a predetermined period of time during which the second relay prevents the first relay from being reenergized.

Description

United (72] Inventor Filed Patented Priority Appl No.

States atet William David Hull 7 Thirlmere Avenue. Colne. Iianeashire.

England 28.316

Apr. 14. 1970 July 20,1971 May 27. 1969 Great Britain 26,638

CONTROL CIRCUIT FOR A STARTER SOLENOID 3,452,210 1/1969 (irayetal.

ABSTRACT: A control circuit for a vehicle starter solenoid which operates so that a' second attempt to start an engine cannot be made until a predetermined time has elapsed after a first attempt to start the engine. A starter switch energizes a first rely which completes a circuit to the starter solenoid, completes a self-hold circuit to itself and charges a capacitor connected across the base emitter path of a transistor. The transistor then energizes a second relay which opens a contact between the starter switch and the first relay to break the circuit to the first relay other than through the self-hold circuit. The first relay is then deene'rgized when the starter switch is opened so that the capacitor discharges through the baseemitter path of the transistor to keep the second relay energized for a predetermined period of time during which the second relay prevents the first relay from being reenergized.

PATENTEU JULPO I97! AT NE S CONTROL CIRCUIT FOR A STARTER SOLENOID ON A VEHICLE This invention relates to a control circuit for a starter solenoid on a vehicle, and has for its object to provide such a circuit in a form in which a second attempt to start the engine cannot be made until a predetermined time has elapsed after a first attempt to start the engine.

A control circuit according to the invention includes a starter switch, a'first relay which is energized when the starter switch is closed, the first relay when energized serving to complete a circuitto the starter solenoid, complete a self-hold circuit to itself, and charge a capacitor connected across the base-emitter path ,of a transistor and turn the transistor on, the

transistor then energizing a second relay which opens a contact between the starter switch and the first relay to break the circuit to the first relay other than through the self-hold circuit, the first relay being deenergized when the starter switch is opened and the capacitor then discharging through the base-emitter path of the transistor to keep the second relay energized for a predetermined period of time during which the second relay prevents the first relay from being reenergized even if the starter switch is closed.

The accompanying drawing is a circuit diagram illustrating one example of the invention.

Referring to the drawing, a road vehicle includes a battery 11 having its negative terminal earthed and its positive terminal connected to the movable contact 12 of an ignition switch. The contact 12 is movable from the off position shown to a first position in which it completes a circuit to a contact 13 providing power to the ignition control circuits of the vehicle, or the auxiliary loads in the case of a diesel-engined vehicle, the contact further being movable to a second operative position in which it completes a circuit to the contact 13 and a contact 14. The contact 14 is connected to one end of the starter solenoid 17 of the vehicle through a normally open contact 16a of a first relay having a coil 16, the other end of the solenoid 17 being earthed, and the solenoid 17 when energized serving to operate the starter motor of the vehicle. The junction of the contact 1611 and solenoid 17 is connected to the anodes of a pair of

diodes

18, 19 the cathode of the diode 18 being earthed through the winding 16, and further connected to the contact 14 through the normally closed contact 15a of a second relay having a coil 15. The cathode of the diode 19 is connected to earth through a capacitor 23, and is further connected through a variable resistor 22 to the base of an NPN transistor 21, the emitter of which is earthed and the collector of which is connected through the winding 15 to the contact 12.

When the contact 12 is moved into engagement with the contact 14 to start the engine, the circuit is completed by way of the contact 15a and the winding 16 to energize the first relay, so closing the contact 16a and energizing the solenoid l7. Closure of the contact 16a also completes a self-hold circuit to the winding 16, and charges the capacitor 23 and then turns the transistor 21 on, so that the winding 15 is energized to open the contact 15a, the winding 16 then being energized solely through the contact 16a and diode 18 When the contact 12 is moved out of engagement with the contact 14, the winding 16 is deenergized and the contact 16a opens to break the circuit to the solenoid l7. However, at this stage the contact 15a is still open, and the transistor 21 remains energized 'tor a predetermined period of time during which the capacitor 23 discharges through the resistor 22. During this period of time, the contact 15a remains open so that if another attempt is made to start the engine, no circuit is completed to the winding 16.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A control circuit for a starter solenoid on a vehicle, including a starter switch, a first relay which is energized when the starter switch is closed, the first relay when energized servmg to completea circuit to the starter solenoid, completes a self-hold circuit to itself, and charge a capacitor connected across the base-emitter path of a transistor and turn the transistor on, the transistor then energizing a second relay which opens a contact between the starter switch and the first relay to break the circuit to the first relay other than through the self-hold circuit, the first relay being deenergized when the starter switch is opened and the capacitor then discharging through the base-emitter path of the transistor to keep the second relay energized for a predetermined period of time during which the second relay prevents the first relay from being reencrgized even if the starter switch is closed.

Claims

1. A control circuit for a starter solenoid on a vehicle, including a starter switch, a first relay which is energized when the starter switch is closed, the first relay when energized serving to complete a circuit to the starter solenoid, completes a self-hold circuit to itself, and charge a capacitor connected across the base-emitter path of a transistor and turn the transistor on, the transistor then energizing a second relay which opens a contact between the starter switch and the first relay to break the circuit to the first relay other than through the self-hold circuit, the first relay being deenergized when the starter switch is opened and the capacitor then discharging through the base-emitter path of the transistor to keep the second relay energized for a predetermined period of time during which the second relay prevents the first relay from being reenergized even if the starter switch is closed.