Vehicle starter with integrated thermal protection

Patent metadata

Field	Value
Publication number	US-11473546-B2
Application number	US-202017117726-A
Country	US
Kind code	B2
Filing date	Dec 10, 2020
Priority date	Dec 19, 2019
Publication date	Oct 18, 2022
Grant date	Oct 18, 2022

Abstract

A starter assembly which includes a switch for energizing a solenoid. Energizing the solenoid biases a starter gear into engagement and energizes the starter motor. A thermally responsive switch is positioned to absorb heat generated by operation of the electric motor and is disposed in an electrical line controlling operation of the switch controlling the solenoid wherein opening of the thermally responsive switch results in the opening of the solenoid switch. The use of such a thermally responsive switch de-energizes the electric motor when the electric motor is subjected to elevated operating temperatures that might otherwise cause damage to the electric motor. The starter assembly may also include control circuitry that includes a microprocessor wherein the control circuitry is operably coupled with the switch controlling the solenoid. The control circuitry is programmed to de-energize the solenoid upon the satisfaction of predetermined conditions to thereby prevent damage to the electrical motor.

First claim

What is claimed is:

1. A starter assembly for an internal combustion engine, the starter assembly adapted to work with a voltage source and the internal combustion engine to start the engine, the starter assembly comprising:
an electric motor which drives a starter gear, the starter gear being selectively shiftable between an engaged position and a disengaged position wherein in the starter gear is operably coupled with the internal combustion engine in the engaged position and is decoupled from the internal combustion engine in the disengaged position wherein the electric motor is mounted within a main housing, the main housing being grounded;
a solenoid coupled with the starter gear wherein energizing the solenoid shifts the starter gear into the engaged position and wherein the starter gear is biased to the disengaged position when the solenoid is de-energized; and wherein energizing the solenoid closes a motor switch, the motor switch being disposed in a first electrical line adapted to couple the electric motor with the voltage source whereby closing the motor switch energizes the electric motor and opening the motor switch de-energizes the electric motor;
a solenoid switch disposed in a second electrical line in communication with the solenoid wherein closing the solenoid switch energizes the solenoid and opening the solenoid switch de-energizes the solenoid wherein the solenoid switch is disposed in a switch housing, the switch housing being mounted on and electrically isolated from the main housing;
control circuitry including a microprocessor operably coupled with the solenoid switch, the control circuitry being in communication with a motor voltage sensing line whereby the control circuitry is responsive to voltage changes in the electrical motor, the control circuitry also being in communication with an electrical line in communication with the voltage source whereby the control circuitry is responsive to the voltage of the voltage source, the control circuitry being programmed to open the solenoid switch upon the satisfaction of predetermined conditions to thereby prevent damage to the electrical motor;
wherein the control circuitry is mounted within a control unit housing, the control unit housing being attached to the switch housing;
a vibrational dampening and electrically isolating mounting assembly for securing the control unit housing and the switch housing to the main housing wherein the mounting assembly electrically isolates the main housing from the control unit housing and from the switch housing; and
a thermally responsive switch positioned to absorb heat generated by operation of the electric motor and wherein the thermally responsive switch opens when experiencing elevated temperatures, the thermally responsive switch being disposed in a third electrical line operably coupled with the solenoid switch wherein energizing the third electrical line closes the solenoid switch and de-energizing the third electrical line opens the solenoid switch, and wherein the third electrical line is grounded by attachment to the starter assembly, the thermally responsive switch being disposed in the third electrical line between the solenoid switch and the ground wherein opening of the thermally responsive switch prevents energizing of the third electrical line and results in the opening of the solenoid switch by opening the third electrical line and thereby preventing the grounding of the solenoid switch and the control circuitry.

2. The starter assembly of claim 1 wherein the third electrical line also includes a user operated switch.

3. The starter assembly of claim 1 wherein the solenoid switch is a magnetic switch and the third electrical line forms coils of the magnetic switch.

4. The starter assembly of claim 3 wherein the third electrical line includes a user operated switch and extends, in series, from the voltage source to the user operated switch, to the magnetic switch, to the thermally responsive switch, to a ground.

5. The starter assembly of claim 3 wherein the thermally responsive switch is disposed in the third line between the switch housing and the main housing.

6. The starter of claim 1 wherein the thermally responsive switch is a bimetallic switch.

7. The starter system of claim 1 wherein the thermally responsive switch is mounted on and absorbs heat from the brush plate assembly of the electric motor.

8. The starter assembly of claim 1 wherein the control circuitry includes a MOSFET switch, the MOSFET switch being disposed in the third electrical line controlling operation of the solenoid switch wherein opening of the thermally responsive switch results in the opening of the solenoid switch, the MOSFET switch being disposed in series with the thermally responsive switch.

9. The starter assembly of claim 8 wherein the thermally responsive switch is operable to open the electrical line controlling the operation of the solenoid switch in the event of a short circuit of the MOSFET switch to a closed configuration.

10. The starter assembly of claim 9 wherein the control circuitry is programmed to:
a) require a delay between sequential closings of the solenoid switch of at least three seconds;
b) prevent the closing of the solenoid switch when the voltage of the voltage source exceeds a predetermined engine running voltage threshold;
c) prevent the closing of the solenoid switch if the voltage of the voltage source falls below a predefined first low voltage threshold;
d) open the solenoid switch if the voltage of the voltage source falls below a predefined second low voltage threshold, the second low voltage threshold being lower than the first low voltage threshold;
e) open the solenoid switch after passage of a predetermined time limit with the solenoid switch closed;
f) wherein the thermally responsive switch is disposed in the third electrical line and wherein the third electrical line also includes a user operated switch and, when the user operated switch is closed and the voltage of the electric motor falls below a predetermined threshold, the solenoid switch is momentarily opened and then closed and, if the voltage of the electric motor does not rise above the predetermined threshold and three such sequential opening and closing of the solenoid switch are conducted, the solenoid switch is opened; and
g) wherein the control circuitry is responsive to the voltage in an electrical line containing the user operated switch and the solenoid switch is opened if, after closing the solenoid switch and energizing the solenoid, the voltage of the electrical line containing the user-operated switch rebounds above a predetermined threshold.

11. The starter assembly of claim 10 wherein the user operated switch is required to be closed to close the solenoid switch.

12. The starter system of claim 1 wherein the thermally responsive switch is a bimetallic switch and the third electrical line also includes a user operated switch;
wherein the solenoid switch is a magnetic switch and the third electrical line forms coils of the magnetic switch and extends, in series, from the voltage source to the user operated switch, to the magnetic switch, to the thermally responsive switch, to a ground; and wherein the third electrical line is grounded by connecting it to the main housing, the thermally responsive switch being disposed in the third line between the switch housing and the main housing.

13. The starter assembly of claim 12 wherein the control circuitry includes a MOSFET switch, the MOSFET switch being disposed in the third electrical line controlling operation of the solenoid switch wherein opening of the thermally responsive switc

Assignees

• Borgwarner Inc

Inventors

• Kirk Michael E
• Whitlock Jr William P
• Andis Randy L
• Spangler Rodney E

Classifications

• F02N11/106

  for stopping or interrupting starter actuation · CPC title

• F02N11/10

  Safety devices (F02N11/08 takes precedence) · CPC title

• H01H51/065

  Relays having a pair of normally open contacts rigidly fixed to a magnetic core movable along the axis of a solenoid, e.g. relays for starting automobiles (details H01H50/20) · CPC title

• F02N11/087 Primary

  Details of the switching means in starting circuits, e.g. relays or electronic switches · CPC title

• F02N11/105

  when the engine is already running (F02N11/0848 takes precedence) · CPC title