Vehicle starter and electrical system protection

• US 5,413,072 A
• Filed: 12/10/1993
• Issued: 05/09/1995
• Est. Priority Date: 08/15/1991
• Status: Expired due to Term

• Current Assignee: Uusi LLC (Nartron Corporation)
• Original Assignee: Nartron Corporation
• Inventors: Gebauer, Duane W., Ingraham, Ronald D., Andersen, Christian J.
• Primary Examiner(s): Dolinar, Andrew M.
• Application Number:
  US08/165,968
• Time in Patent Office: 515 Days
• Field of Search: 123/179.6, 123/179.21, 123/145 A, 219/501, 219/506, 361/265, 361/264, 340/640
• US Class Current: 123/145.00A
• CPC Class Codes: F02D 2041/228 Warning displays
• CPC Class Codes: F02N 11/0848 with means for detecting successful engine start, e.g. to stop starter actuation
• CPC Class Codes: F02N 11/105 when the engine is already running F02N11/0848 takes precedence
• CPC Class Codes: F02P 19/02 electric, e.g. layout of circuits of apparatus having glowing plugs

Abstract

A protective control box is disclosure for providing protection for a starter system and other components of equipment, such as vehicles, incorporating internal combustion engines. Improved starter protection apparatus and circuitry using frequency to voltage conversion disables a starter motor from starting the internal combustion engine when engine speed exceeds a pre-determined level. The starter cannot be re-actuated until and unless engine speed has fallen below a second lower pre-determined speed level. The protection box includes a lockout solenoid which in turn selectively locks out the main starter solenoid in accordance with the foregoing conditions. A wait-to-start lamp and associated comparator and latching circuitry is provided for actuating the wait lamp in response to initiation of glow plug controller pre-glow operation, and for subsequently extinguishing the lamp. Once extinguished, the lamp cannot be re-actuated until and unless the ignition has been toggled. Circuitry including a field effect transistor is provided for controlling glow plug controller operation by means of an auxiliary solenoid. Load dump control circuitry responsive to frequency to voltage conversion inhibits disconnection of electrical loads from a motor-driven alternator even when the ignition is turned off, until engine speed has dropped to a safe level. This prevents voltage spikes which would otherwise result from the sudden unloading of the alternator, a phenomenon which could damage a voltage regulator or other electrical circuitry. After-glow control maintains glow plug controller operation until ambient engine temperature has reached a pre-determined level.

Claims

1. A glow plug actuation indicator for equipment having an internal combustion diesel engine including at least one glow plug, an engine ignition switch, toggleable between an on and an off position, and a glow plug controller circuit for energizing the glow plug in a pre-glow mode of operation for a period of time subsequent to the engine ignition switch being toggled to the on position, the controller circuit generating a signal at an output node when the glow plug is energized in the pre-glow mode of operation, said glow plug actuation indicator comprising:

a) a wait-to-start lamp actuated when the glow plug is energized in the pre-glow mode of operation;

b) a voltage regulator circuit coupled to the ignition switch generating a voltage signal at an output node when the ignition switch is in the on position; and

c) lamp actuation circuitry coupled to the wait-to-start lamp, the controller circuit output node and the voltage regulator circuit output node for actuating said lamp in response to a signal at the controller circuit output node indicative of pre-glow operation of said glow plug and the ignition switch is in the on position, the lamp actuation circuitry including;

i) a switch coupled to the lamp for actuating said lamp;

ii) a timing circuit;

iii) a comparator having first and second input terminals and an output terminal for activating the switch, the output terminal being connected to the switch and further being coupled to the voltage regulator circuit output node, one of the first and second input terminals connected to the timing circuit and the other of the first and second input terminals coupled to the controller circuit output node, the comparator generating a high output signal when a signal magnitude at the input terminal coupled to the controller circuit output node exceeds a signal magnitude at the input terminal connected to the timing circuit;

iv) the switch being turned on when both the ignition switch is in the on position and the comparator output signal is high.

2. The glow plug actuation indicator of claim 1 wherein the timing circuit comprises a capacitor charging circuit.

3. The glow plug actuation indicator of claim 2 wherein the capacitor charging circuit is coupled to the voltage regulator circuit output node and is energized thereby.

4. The glow plug actuation indicator of claim 1 wherein the switch comprises a switching transistor and the comparator output terminal is connected to a base terminal of the switching transistor.

5. The glow plug actuation indicator of claim 4 wherein a collector terminal of the switching transistor is coupled to the wait-to-start lamp.

6. The glow plug actuation indicator of claim 1 wherein the lamp actuation circuitry further includes latching circuitry to inhibit the reactuation of the wait-to-start lamp prior to subsequent toggling of the ignition switch.

7. A power control system for controlling application of high electrical power to a glow plug in an internal combustion diesel engine to actuate the plug in a pre-glow mode of operation for a period of time subsequent to toggling an ignition switch to an on position, the engine having associated therewith a glow plug controller including circuitry for generating an output signal at an output node indicating that the glow plug is to be actuated in the pre-glow mode of operation, said power control system comprising:

a) a solenoid coupled to said glow plug, the solenoid actuating the glow plug in the pre-glow mode of operation when a high power signal is applied to the solenoid;

b) circuitry coupled to the glow plug controller output node and to the solenoid whereby a high power signal is applied to the solenoid when said glow plug controller output signal is present at the glow plug controller output node, said circuitry comprising;

i) a field effect transistor coupled to the glow plug controller output node and the solenoid, the field effect transistor adapted to be turned on when the output signal is present at the glow controller output node and be turned off otherwise; and

ii) voltage regulation and transistor actuation circuitry including a pair of matched transistors coupled between the glow plug controller output node and said field effect transistor for providing a regulated source of voltage to a gate of the field effect transistor for gating said field effect transistor such that the transistor is turned on in response to the output signal at the glow plug controller output node.

8. The power control system of claim 7 wherein the field effect transistor is a P-channel enhancement-mode power field effect transistor.