Starter motor protection system

• US 5,345,901 A
• Filed: 07/26/1993
• Issued: 09/13/1994
• Est. Priority Date: 07/26/1993
• Status: Expired due to Fees

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Reason, John R., Siegenthaler, David R., Lane, L. Thomas
• Primary Examiner(s): Dolinar, Andrew M.
• Application Number:
  US08/097,143
• Time in Patent Office: 414 Days
• Field of Search: 123/179.3, 290/38 R
• US Class Current: 123/179.3
• CPC Class Codes: F02N 11/0851 characterised by means for controlling the engagement or disengagement between engine and starter, e.g. meshing of pinion and engine gear
• CPC Class Codes: F02N 11/087 Details of the switching means in starting circuits, e.g. relays or electronic switches
• CPC Class Codes: F02N 11/10 Safety devices F02N11/08 takes precedence
• CPC Class Codes: F02N 2200/047 Information about pinion position

Abstract

An engine starter has a plunger electromagnetically actuated by holding and attracting coils to move a pinion toward a ring gear on the engine and also to move a first movable contact on the plunger towards first and second stationary contacts to be electrically connected together by the first movable contact to electrically energize a starter motor. Completion of the circuit between the movable contact and the stationary contacts also serves to de-energize the attracting coil which may be damaged if energized for too long. Control means are provided to determine the voltages at each of the fixed contacts. The difference between the monitored voltages is determined and compared to a reference voltage differential. If the difference is not less than or equal to the reference voltage differential, the controller is programmed to know that the circuit has not been completed, and in order to avoid damage to the attracting coil and the starter, power is interrupted to the starter circuit.

Claims

1. A starter for an internal combustion engine having a ring gear, the starter including:

a starter switch, operable between an open and closed condition, adapted to be electrically connected to an electrical power source;

a pinion adapted to be axially movable into and out of meshing engagement with the ring gear;

a plunger for moving said pinion toward said ring gear and having a movable contact at one end thereof;

first and second stationary contacts both so positioned as to be contacted by said movable contact, said first stationary contact being electrically connected to said electrical power source;

exciting coil means for moving said plunger toward first and second stationary contacts, said exciting coil means comprising a holding coil and an attracting coil, said holding and attracting coils having windings electrically connected in series with one other and having a connection coupled thereto at respective one ends of said holding and attracting coils;

a relay including;

(a) a pair of normally open contacts connected in series to said electrical power source and said connection coupling said windings of said holding and attracting coils, and, (b) a relay coil electrically connected in series to said starter switch and the other end of said holding coil, and which is energized when said starter switch is turned on, to thereby close said normally open contacts;

a starter motor, said starter motor being drivingly connected to said pinion;

means for electrically connecting said second stationary contact to said starter motor when said starter switch is closed, whereby, when said first movable contact is moved into contact with said first and second stationary contacts to electrically connect them together, said starter motor will be energized by said electrical power source;

a motor controller comprising;

means for determining the voltage at said first stationary contact;

means for determining the voltage at said second stationary contact;

means for calculating the voltage difference between said first stationary contact and said second stationary contact;

means for comparing said calculated voltage difference to a predetermined reference voltage differential, and, if the calculated voltage differential is not less than or equal to said predetermined reference voltage differential interrupting the power supply to said relay coil.

2. The apparatus of claim 1 wherein said motor controller comprises a programmable microprocessor.

3. The apparatus of claim 2 further including:

a switch, electrically operable between a conducting and non-conducting condition located in the circuit supplying said relay coil; and

wherein said controller generates a signal to open said electrically operable switch to interrupt the power supply to said relay coil.